View Full List of National Register: Wyoming Listings

Expedition Island, near the present day town of Green River, Wyoming, was the starting point for the two expeditions down the Green and Colorado Rivers led by Major John Wesley Powell in 1869 and 1871. On these expeditions Powell completed the exploration of the last, large, unknown land area in the continental United States. Exploration of the unknown Colorado River by Powell and his crew opened up a new era for the nation. New concepts of conservation, reclamation, forestry and water management, geological and geographical surveys, and a whole new and scientific approach to the western lands ensued.