1853: Congress was studying four possible routes for building a transcontinental railroad to the Pacific coast. Supporters of a southern route wanted to extend the railroad at New Orleans westward to California. They pressured Congress into spending $10 million for a small strip of land and the southern end of the Rocky Mountains which would provide a level route to the west coast. The Gadsden Purchase, as the land area was called, was obtained from Mexico by foreign minister James Gadsden. The Gadsden Purchase, now part of southern Arizona and New Mexico, completed the acquisition of land that today makes up the continental United States.