Wheeler led early expeditions from 1869 to 1871 in the West, and in 1872 the United States Congress authorized an ambitious plan to map the portion of the United States west of the 100th meridian at a scale of eight miles to the inch. This plan necessitated what became known as the Wheeler Survey. The survey's main goal was to make topographic maps of the southwestern United States.
In addition he was to ascertain everything related to the physical features of the region; discover the numbers, habits, and disposition of Indians in the section; select sites for future military installations; determine facilities available for making rail or common roads; and note mineral resources, climate, geology, vegetation, water sources, and agricultural potential.[5]
Photographers on the expedition included Timothy H. O'Sullivan of New York and William Bell of Philadelphia. Many of their photographs are now on file at the Library of Congress's Prints and Photographs Division.[6][7]
The Wheeler Survey lasted until 1879, when the survey, along with the King and Powell Surveys, were terminated and their work was reorganized as the United States Geological Survey.