Transcontinental Railroad Surveys
The largest government funded effort to explore and survey the American west for potential routes of four transcontinental railroads.
Following the Treaty of Guadaloupoe Hidalgo ending the Mexican-American War and the discovery of gold in California, Secretary of War Jefferson Davis was directed by congress under the provisions of the Army Appropriation Act, to survey possible routes to the Pacific. Four east to west routes, roughly following specific parallels, as well as a north-south route through the coastal states of Washington, Oregon, and California were to be surveyed by parties under the supervision of the Topographical Corps.
The maps that came from this extraordinary surveying effort present the most accurate cartographic depiction of the American West that include the locations of many Native American tribes, topographic information, places where water can be found, and the tracks of explorers from years past as well as well trodden trails once used by Spanish Conquistadores of the 16th and 17th century.