G.W. & C.B. Colton, Map of the States and Territories West of the Mississippi River (1868)

As stated in the title, this map from G.W. and C.B. Colton shows the overland routes and projected railroads in the United States as of the year 1867. Stanford University Libraries notes in their online exhibit of the First Transcontinental Raiload "that the routes of the explorers and surveyors are clearly delineated, belying the appearance that the nation has been settled from coast to coast." By the time this map was created, five years after the passage of the Pacific Railway Act, the Central Pacific Railroad had been completed to Truckee Pass, the north/south California railroad had been completed from San Francisco to around present-day Salinas, and the Union Pacific line had been completed nearly to Cheyenne Pass in present-day Wyoming. The map includes information from the Pacific Railroad Surveys such as notes on topography, land cover, and even the spot where Captain John W. Gunnison was killed on a surveying expedition to Utah. In just over thirty years after the creation of this map, the railroad network of the United States was nearly complete, forever transforming the patterns of settlement throughout the United States.