The Bishop Family Home was constructed in 1907, one of the earliest multi-story brick houses in Casper. The residence is an example of a Four Square Home with colonial revival details, reminiscent of the Virginia boyhood home of the original owner, Marvin Lord Bishop, Sr. The home has been continuously owned and occupied by the Bishops, one of Casper's original pioneer families.

The Casper Federal Building is a massive three-story Classical Revival style office building composed of reinforced concrete and brick tiles faced with red pressed brick trimmed with Wyoming sandstone. It was erected in 1932 to house the post office, the federal court system, and other federal agencies. The building reflects the expansion of federal facilities in the United States during the early twentieth century. The interior is significant for its District Courtroom with original wood paneling, millwork, and trim, and its judge's bench, witness box, and elaborated entrances. The building represents the work of the Office of the Supervising Architect of the Treasury Department during the tenure of James A. Wetmore. The building was formally renamed the ''Ewing T. Kerr Federal Building in 1992. Kerr was a former Wyoming Attorney General and U.S. District Court judge. The building is now occupied by the U.S. District Court, the US. Bankruptcy Court, the U.S. Attorney, and the U.S. Marshal.

The Casper Army Air Base is one of only four World War II military installations constructed in Wyoming (the other three installations were the Prisoner of War Camp at Douglas, the Heart Mountain Relocation Center between Cody and Powell, and the quartermaster facility at Fort F.E. Warren in Cheyenne). The Base was activated on September 1, 1942. Over four hundred buildings were built during a three and one-half month construction period. It was occupied by the 211th Army Air Force Base Unit consisting of twenty-one officers and 165 enlisted men, whose mission was to operate the base and train bomb groups for overseas assignment and individual replacement bombardment combat crews. During its thirty months of active life, the Base trained an estimated 16,000 combat crew members. The Base was officially deactivated on March 7, 1945 and personnel were transferred to other bases. In 1949, the former military air field became the Natrona County Municipal Airport and the land and all buildings became county property. Approximately one hundred of the original buildings that constituted the Casper Army Air Base, along with the original street layout, parade grounds, and concrete pads for many of the former buildings, remain.

The Casper Buffalo Trap is a Paleoindian bison kill site located in a parabolic sand dune south of Interstate 25 on the northwest side of the City of Casper. It is surrounded by industrial and commercial development. The site was excavated by Dr. George Frison of the University of Wyoming in 1971. The animals that were hunted at this site eight to ten thousand years ago is an extinct type of large bison. According to one estimate, the largest males may have weighed as much as two tons. The distance between the tips of the horns on one bison skull measured 42 inches indicating the distance between the horn tips on the once-living animal could have been over five feet. The site has yielded important information regarding prehistoric bison procurement strategies.

The Casper Downtown Historic District comprises the historic business and civic center of the City of Casper, Natrona County, Wyoming. It is eligible for listing in the National Register for its local significance under Criterion A in the area of commerce and Criterion C in the area of architecture. The District includes the contiguous commercial, industrial, social, and governmental resources that retain architectural integrity and continue to reflect the evolution of Casper’s economic center from the late nineteenth century through the post-World War II period. The District encompasses 102 properties constructed between circa 1896 and circa 1980, including seventy-one (71) contributing buildings, one (1) contributing structure, one (1) contributing site, and twenty-three (23) non-contributing buildings. The District is locally significant in the area of commerce for its associations with the growth of C

asper as a county seat, railroad market center, oil industry hub, and regional economic anchor. As county seat and later with the arrival of the railroad, Casper grew to become the railroad agricultural market center of Natrona County and major hub in central Wyoming. The physical and architectural development of the downtown commercial center reflects the importance of the railroad, as well as the Yellowstone Highway, in the community’s commercial history. The District’s resources communicate historic trends in downtown development, physically representing the spectrum of building technology, design, stylistic features, form, and function that define the history of Casper. The District’s period of significance begins in circa 1896 with the construction of the earliest building and ends at the construction of the latest contributing building in 1970. The period of significance acknowledges historic alterations in response to specific functional and marketing needs and counts buildings that experienced such alterations within the period of significance as contributing elements to the District.

The Casper Municipal Garage and Fire Station, also known as the Casper Fire Department Station #1, was designed in 1921 by the city's leading architectural firm of the day, Garbutt, Weidner and Sweeney. The brick building has an unusual design and striking late Gothic Revival appearance embellished with buff colored terra cotta around the three garage door openings, upper floor windows, and crenelated parapet. The Casper Fire Station is both architecturally and historically significant. The construction of the fire station in 1921 marked a significant turning point in the community because it reflected a greater need for fire protection in an expanding population. The building is associated with the growth and development of the City of Casper during the oil boom of 1914-1927; the building symbolizes how Casper changed from a small agricultural town with a volunteer fire department to a booming oil center with a paid fire protection staff.

The Church of Saint Anthony was constructed in 1919-1920 and designed by the Casper architectural firm of Garbutt, Weidner and Sweeney. The Church was built of brick and marble with a tile roof. The distinctive square bell tower, tile roof, round arched windows and corbel tables closely resemble churches in Italy and represents the Romanesque Revival architectural style. The Church is significant in the area of architecture as an outstanding example of the Romanesque Revival style in religious buildings and as the work of a master architect, Arthur M. Garbutt.

The Consolidated Royalty or Con Roy Building is a substantial five story brick commercial building located along Center Street, the main street of Casper. Most of the historic office buildings that were constructed in Casper between 1915 and 1927 are now either gone or radically changed. The Con Roy Building is one of the last remnants of the tall office buildings in downtown and is one of a handful of historic buildings that have retained their integrity in the city's commercial core. When designed by the Casper firm of Garbutt and Weidner in 1917, the Con Roy had the architectural elements and design of many of the early ''skyscrapers'' constructed first in Chicago during the late nineteenth century. The Con Roy can be considered an example of the commercial style with neoclassical elements such as the prominent terra cotta cornice, dentil molding, and symmetrical appearance. Some of Casper's leading citizens, such as Patrick J. Sullivan and B. B. Brooks, were instrumental in the development and subsequent occupation of the Oil Exchange Building, later renamed the Consolidated Royalty Building. The building, constructed in response to a need for more office space that was necessary because of the tremendous oil boom, symbolizes the wealth that was part of Casper during a period of prosperity from 1914-1927. The history of the Consolidated Royalty Building is strongly associated with the discovery and commercialization of oil in the Casper area and the need for a prominent office building to house the prosperous oil companies. Construction began on the building in 1917. By the end of 1918 over thirty different entities were listed as occupants of the building in a Casper business directory. The Con Roy Building has continued to serve the community as one of its finest office buildings.

Dean Morgan Junior High School was the first separate building constructed specifically for junior high school students in Casper. The original section was built in 1951-53 and was part of a statewide school building program implemented at the conclusion of World War II. This building program was necessitated by a dramatic increase in the number of students enrolled in schools throughout the state. The school is a striking example of mid-century modernist architecture designed by Casper architect Karl Krusmark. Dean Morgan is one of the best preserved surviving examples of Wyoming’s post World War II school facilities.

Elks Lodge No. 1353 was constructed from 1920-1922 by the prominent architectural firm of Garbutt, Weidner and Sweeney during the 1920s oil boom in Casper. It is a two-story brick building with distinct horizontal divisions utilizing pronounced terra cotta belt courses. The building elements are representative of the Second Renaissance Revival architectural style. On March 17, 1922, the Casper Elks celebrated the opening of the new lodge building with an initiation of a large class, installation of officers, a business program, entertainment, and a midnight dinner. In May the Elks held a minstrel show in their new home in the 900-seat auditorium. According to early descriptions, the interior of the building originally consisted of a banquet room in the basement with adjoining serving rooms, dish closets and kitchens. A dumb waiter connected the downstairs serving rooms with a lunch room on the first floor. The basement also contained janitors quarters, locker rooms, shower rooms and a gymnasium. The main entrance on the first floor led into a vestibule of marble and ''caen'' stone with terrazzo floors. From there a large lobby and corridors led into the first floor rooms including a billiard room, lounge, ladies' dining and lunch room, dining room and card room for men, and secretary's office. The building is architecturally significant as an outstanding example of Second Renaissance Revival architecture and as the work of a master architect, Arthur M. Garbutt.

Fort Caspar is named for Caspar Collins, a lieutenant killed while trying to rescue a blockaded wagon train in 1865. Until that time the fort had been called Platte Bridge Station. Fort Caspar derives its primary significance from the concentration of many important events and activities. Early fur trade caravans passed this point regularly each season during the peak of trade in the region and used the ford to cross the North Platte. In addition, most travelers to California and Oregon from the 1840s through the 1860s traveled past this location and used the crossing. The transcontinental mail route passed here in 1851 and a stagecoach line used the route from 1858-1862. The Fort was established in order to protect the Platte River Bridge which was built in 1858 and used until late 1867. The Army garrisoned the site from 1858-1859 and again from 1862-1867.

The dominant structure throughout the 1858-1867 period was Guinard's Platte Bridge. Louis Guinard had a small residence and store near the south end of the bridge. This was expanded to house a telegraph station in 1861. The precise nature and location of the 1858-1859 army buildings are not known. However, ground plans and drawings cover the 1863 period structures which housed the telegraph station garrison. These, along with archaeological data, formed the basis for the reconstruction of the 1863 structures completed in 1939. During 1865-1867 the army expanded the post considerably. Excellent plans and elevations along with materials lists and specifications cover this construction period. The buildings were of log construction, with plank floors and roofs of puncheons, covered with clay. At its peak of development the post included over two dozen substantial buildings and additional lesser outbuildings, and housed from three hundred to four hundred men, one of the largest garrisons in the West.

Grant Street Grocery and Market is eligible under Criterion A due to its association with the development of Casper and the stores survival through changing economic climates during the 1920s and continuing oil boom, the Great Depression, World War II, and post-World War II. Established in 1921, Grant Street Grocery served as a family owned grocery and meat market. Over the years, it retained its local neighborhood atmosphere, during varying economic conditions and changes in ownership. Each successive owner adapted the store to fit the needs of the time, yet maintained the store as an essential and integral part of both the immediate neighborhood and the community.

Grant Street Grocery and Market sits in a residential neighborhood on the corner of Grant Street and Divine Avenue. The west façade, which serves as the primary entrance for the store, has changed little from its original construction in 1921. In contrast, the rear or east elevation contains multiple additions. These alterations, while appearing somewhat haphazard, expanded the store and allowed the owners to provide additional services and products.

The one-story building has a parapet, which hides a gable roof and bears the name Grant Street Grocery. The name, decorative elements, and much of the rear additions are in a dark brown. The majority of the remaining building is tan stucco covering a wood frame that rests on a concrete foundation and is centered on a recessed entrance. Both the north and south side elevations are relatively unadorned; each is tan stucco interrupted by pilasters.

The east elevation, which is the rear of the store, underwent multiple additions since construction in 1921. The various changes obscure much of the original construction. According to county records, the only major additions occurred in 1937; however, the appearance of this elevation indicates multiple, somewhat jumbled alterations, which seemed to occur over time.

The integrity of the store remains, as the alterations occurred within the period of significance. The additions illustrate the changes required to maintain a business for over eight decades. Sitting in the same location, surrounded by the neighborhood it maintains the same feeling and association of a small community business.

The interior of the store also maintains both the feeling and association of a small neighborhood market. The basic size and shape of the store remains from construction in 1921. Only the depth has changed as owners added, altered, or expanded the rear of the store and the back rooms to fit their needs. According to current owner, Bill Wayte, a few of the store’s older fixtures still remain. The refrigeration unit, currently holding imported cheese, dates from the mid-1930s and the original butchers block still survives, now used to serve gourmet sandwiches. Although interior display arrangements and layouts may have varied over the past 87 years, the overall feeling is retained. It is a local market serving the surrounding neighborhoods.

Casper experienced an oil boom period that began in 1913-14 and continued well into the next decade. The major oil companies established their headquarters in Casper, providing employment and injecting capital into the local economy. The population of 2,639 in 1910 nearly doubled in the next five years to 4,040. Casper transformed during the decade and a half boom as the population continued to increase at a staggering rate.

The rising population and the sudden prosperity accelerated community development and the construction of new buildings. This expansion demanded additional local services within walking distance of people's homes. As the city expanded, the neighborhood grocery store became a common sight; in 1923, 60 neighborhood grocery stores existed in Casper.

Among these 60 was the Grant Street Grocery and Market, which is south of downtown Casper in a residential neighborhood. E.R. Williams owned several neighborhood grocery stores including Central Grocery and Market, established in 1915, Blue Front Grocery, established in 1916, and the Grand Grocery, established in 1921. In 1921, Williams built the Grant Street Grocery as a small local market. A severe depression following World War I left E. R. Williams struggling financially. He chose to lease Grant Street Grocery and Market to Arthur L. LaClair in 1926. Six years later, Arthur ''Art'' LaClair and his wife, Mary, purchased the store from E. R. Williams. As an established store, the market never closed during the transfer of ownership.

In order for the business to succeed, the LaClairs expended great effort to make Grant Street Grocery and Market the best in both products and service. Arthur traveled to meat markets south of Buffalo, Wyoming to procure quality pork, while ordering butter from Sheridan, Wyoming and cottage cheese from Seattle, Washington. During the holidays, he drove 100 miles east of Casper to Lusk and hand picked turkeys, which he then delivered. The LaClairs not only delivered during the holiday season, but also offered deliveries six days a week. Striving to continue the best service to their customers, fresh flowers were also available. Adding to the personal service, neighborhood children always received a cookie when they entered Grant Street Grocery; Arthur LaClair became known as the ''Cookie Man.''

According to local residents, the store expanded as LaClair, who insisted on selling the best meats, built a chicken house at the back of the store. In this building, he fattened, butchered, and dressed his own chickens, turkeys and other small poultry. With the addition of the chicken house, the store then had access to fresh eggs.

In an effort to increase economic viability during the Great Depression, the LaClairs again altered the building and increased the services offered. They enlarged the store to include a bakery, the first in-store bakery in Casper. According to county records, in 1937 the LaClairs built an addition at the rear of the building into which they relocated the chicken house. The new bakery then moved into the old chicken room. These changes proved to be an advantage to the store as the economic instability required different avenues of revenue.

The current owners wanted to maintain the local market tradition. Bill and Nancy Wayte purchased Grant Street Grocery and Market in 2004. They still have charge accounts and a regular clientele of 250 customers, most of whom they know by name. In order to increase business, they now offer a selection of specialty items and gourmet sandwiches, added an imported cheese line, and still have the best meat in town. As a local resident stated, this is ''not a store - it is a market with a little bit extra.''

Grant Street Grocery and Market was established in 1921 during the oil boom and expansive growth of Casper. It continued to serve the neighborhood through various financial climates. The owners sustained the market by maintaining a local atmosphere, providing quality service and products, and adapting to the changing economic environment. Grant Street Grocery survived and remains the sole neighborhood grocery store in Casper.

Martin's Cove is one of a number of handcart company campsites along the North Platte-Sweetwater segment of the Oregon Trail. The cove was not a natural landmark common to all Oregon Trail travelers such as Independence Rock, Devils Gate or Split Rock; rather it is a topographic feature of the Oregon Trail landscape that derives its historic significance as a temporary place of refuge for handcart emigrants. During an early winter storm in October and November of 1856 a party of Martin Handcart Company emigrants perished. More than the site of this tragedy, however, Martin's Cove is a symbol of the physical strain and hardship suffered by many who sought a better way of life.

The Masonic Temple, constructed in 1914, is located at 105 North Center Street, in the northern portion of Downtown Casper. It was designed by a local architect, Homer F. Shaffer, during a period of unprecedented city growth precipitated by the Salt Creek oil boom. It is a brick masonry building with a raised basement level, one of the most imposing edifices in Casper.

Built with permanence in mind, the temple reflects the confidence of its citizens in the future of their city. Many of the important buildings in the commercial district were constructed during this time period, and the Masonic Temple was among the finest built. The Masonic Temple also represents the importance of the Masons to the Casper community, as its membership was composed of many of the leading professionals, civic leaders, and businessmen.

Although portions of the interior have been remodeled, the exterior of the building remains largely intact with only minimal changes. It retains several notable architectural embellishments, including the rusticated stone arched entrance with radiating voussoirs and keystone and a crenellated brick parapet capped with stone. Due to its size and corner location, the Masonic Temple is one of the key components of the remaining commercial district in Casper.

Portions of Natrona County, Wyoming experienced rapid growth during the early twentieth century. Traditionally an agricultural area, various factors influenced this expansion. The creation of Midwest Oil Company and the completion of a pipeline from Salt Creek to Casper in 1911 acted as a tremendous economic catalyst for the county. Casper's population dramatically increased between the years of 1910 to 1920 and the influx of newcomers strained local housing and recreational facilities. Midwest Refinery Company constructed this hotel for its employees around 1920. It was utilized for both housing and social purposes. Later, Standard Oil purchased the hotel. During the twenties, Natrona County's oil production leveled off and by 1930 the world-wide economic depression had a profound effect on the local oil industry. In response to the depressed conditions, Standard Oil sold their hotel to a local women's group. The hotel was utilized as a center for a number of women's organizations. The Casper Women's Clubhouse played a significant role in the social life of this isolated Wyoming community. The building is architecturally important as an example of the work of the architecture firm of Garbutt and Weidner, and is historically important due to its association with social and humanitarian projects beginning in the 1930s.

Natrona County High School, built between the years 1924 and 1941, is one of the city and state's most distinctive high schools. The architectural style, Collegiate Gothic, is highlighted by a dramatic entry tower and the extensive use of terra cotta that draws attention to the building's memorable facade. Constructed after the 1920s oil boom in Casper, the architectural firm of Garbutt, Weidner and Sweeney designed an educational facility with numerous amenities unknown in Wyoming at that time such as in indoor swimming pool. The physical appearance of Natrona County High School, its conception, and its growth are closely intertwined with the economic growth of Casper and the evolution of progressive ideas about education sweeping the country. The laying of its cornerstone in 1924 coincided with the emergence of the modern high school in America. For decades it was the only high school in Casper, and it also housed Casper College from 1944-1955. The building is important for its direct association with the growth of education in Casper, and in the area of architecture as an outstanding example of the Collegiate Gothic style in educational buildings, and as the work of a master architect, Arthur M. Garbutt.

This building was constructed in 1918 by Albert Majors and Benjamin Mueller to house

 the Casper Auto Company, an auto showroom and garage run by B. B. Lummis. The building represents elements of the Mission/Spanish Colonial Revival architectural style. The Natrona/Casper Motor Company building represents one of the earliest and largest car dealerships in Casper and Wyoming. It operated continuously as a car dealership and garage from 1918 to 1970, serving the Casper community and the surrounding region. It is important for its contribution to the commerce of the city and the region. The building is also important for its architecture which reflects the economic optimism and affluence brought about by the regional oil boom of the late 1910s and 1920s. The building facade still retains elements of the Mission/Spanish Colonial Revival architectural style that was in vogue throughout America during this time period. It was also among the first buildings in Casper to be constructed using poured concrete walls.

The North Casper Clubhouse was constructed in 1938-1939 by the North Casper Improvement Association, a local organization composed of interested neighborhood citizens. The clubhouse was built by utilizing labor provided by the National Youth Administration, an agency of the Works Progress Administration, which was a major component of the Roosevelt Administration's New Deal program. The building was designed by the prominent Casper architectural firm of Goodrich and Krusmark. It is a one-story rammed earth building that represents the Pueblo Revival style. Rammed earth construction is an old European building practice utilized by German-Russians on the high plains of North Dakota in the 1880s, and advocated by many federal government agencies as a low cost and durable building technique during the Depression era. It is one of only a few examples of rammed earth construction identified in Wyoming. The building has been used continuously as an important community center where meals are served to senior citizens, church services are held, and wedding receptions are held. The North Casper Clubhouse represents an example of community organization and cooperation in the face of the Great Depression.

The Odd Fellows Building in Casper was completed in 1952 and is an important component of the post-World War II building boom in downtown Casper. At that time the city was developing into a major commercial center in the area. Designed by prominent local firm Goodrich & Wilking, the building is representative of the restrained version of the Modern style of architecture that was becoming increasingly common in Casper in the 1950s. Construction of the building also signaled a renewed interest in fraternal lodges. During the 1950s numerous fraternal organizations built new or expanded their existing lodges. The building was used by the Odd Fellows for over fifty years until 2007 when the lodge disbanded.

The Ohio Oil Company Building, constructed in two stages in 1948-1949 and 1955-1956, displays several basic elements of the Art Deco style of architecture. The building was designed by the architectural firm of Wilbur Watson Associates of Cleveland, Ohio and was constructed to house the division headquarters of the Ohio Oil Company, which became known as the Marathon Oil Company in 1962.