<P> Building a railroad line that connected the United States coast - to - coast was advocated in 1832 when Dr. Hartwell Carver published an article in the New York Courier & Enquirer advocating building a transcontinental railroad from Lake Michigan to Oregon . In 1847 he submitted to the U.S. Congress a "Proposal for a Charter to Build a Railroad from Lake Michigan to the Pacific Ocean", seeking a congressional charter to support his idea . </P> <P> Congress agreed to support the idea . Under the direction of the Department of War, the Pacific Railroad Surveys were conducted from 1853 through 1855 . These included an extensive series of expeditions of the American West seeking possible routes . A report on the explorations described alternative routes and included an immense amount of information about the American West, covering at least 400,000 sq mi (1,000,000 km). It included the region's natural history and illustrations of reptiles, amphibians, birds, and mammals . </P> <P> The report failed however to include detailed topographic maps of potential routes needed to estimate the feasibility, cost and select the best route . The survey was detailed enough to determine that the best southern route lay south of the Gila River boundary with Mexico in mostly vacant desert, through the future territories of Arizona and New Mexico . This in part motivated the United States to complete the Gadsden Purchase . </P> <P> In 1856 the Select Committee on the Pacific Railroad and Telegraph of the US House of Representatives published a report recommending support for a proposed Pacific railroad bill: </P>

Where did the union pacific railroad start and end