The Commerce Block is located at the southeast corner of Birch Street and Fourth Street in downtown Glenrock, Wyoming. It is a two-story, dark red brick commercial building with a flat roof, built in an L-shaped configuration. Its most distinctive feature is its regularly spaced rows of brick pilasters capped with cream-colored terra cotta that divide the west and north finished sides of the building. The building occupies a corner lot and finished facades face both Birch Street and Fourth Street. The east and south sides of the building are unadorned plain tan-colored brick walls or brick covered with stucco.

The building was constructed by Edward A. Reavill, who was an established building contractor in nearby Douglas. The Commerce Block was a key element of the commercial district of Glenrock, and it represents the economic growth of that community in the early 20 th century.

The building was constructed in 1917 during the oil boom of the late 1910s and early 1920s, which was brought about by the discovery and development of the nearby Big Muddy Oil Field and the subsequent construction of two major refineries west of town. The oil industry created jobs for hundreds of employees and related service industries and provided a steady payroll, much of which was injected into the Glenrock economy.