File:Mitchell A New Map of Texas, Oregon, and California 1846 UTA.jpg

English: Published just before the War with Mexico, Mitchell's map embodies the theme of the United States' drive to "fulfill its manifest destiny to overspread the continent." It shows the recently annexed former Republic of Texas in its largest territorial form, including its farthest claims into present New Mexico and Colorado. Looming large in pale yellow is the vast Oregon Territory — until only recently jointly administered by the U.S. and Great Britain and stretching up to the 54º 40' parallel of North latitude. For this area, the map largely followed the printed map of Oregon from the report of Charles Wilkes's expedition. The large pink area labeled "Upper or New California" includes the Mexican territories of Upper California and New Mexico – both of which were soon seized by U.S. forces. This section derived in part from U.S. Army Topographical Engineer Lieutenant William H. Emory's Map of Texas and the Country Adjacent… of 1844, which was a compilation of the best information on what became the American Southwest available in Washington, D.C., before the war with Mexico. It also included up-to-date information obtained by another U.S. Army Topographical Engineer, Lieutenant John C. Fremont, who had first concluded that the continent's interior included a "Great Basin." Mitchell's map calls it "Great Interior Basin of California" where "streams and rivers…have no outlet to the sea." Among the featured trails are the "Oregon route" (with a table inset at lower left of the "Emigrant Route from Missouri to Oregon" giving mileage details), Fremont's alternate route to St. Vrain's Fort near Long's Peak in the Rockies, the "Caravan route to Santa Fe" and beyond this, a route to California by way of "Vegas" and the "Mojave R." leading to the "Great Spanish Trail" from "P. Angeles" to Santa Fe. In the Texas area the map includes old Spanish roads from Louisiana stretching to the Rio Grande and into Coahuila and Tamaulipas, newer roads connecting the rapidly developing multi-colored counties and the old Camino Real or Chihuahua Trail leading south from Santa Fe (in Texas!) along the Rio Grande past "Passo del Norte" to Chihuahua. In far northern Oregon the map traces part of "Mackenzie's route" while further south leading through western Oregon from the "Great Falls" and upper reaches of the Missouri River in "Missouri Territory" is "Lewis and Clark's route" to the Columbia River. With all this information, it is not surprising that Mitchell's commercial map was widely used – Mormon leader Brigham Young ordered six copies for his western migration in the winter of 1846. The map also served as an inset in Mitchell’s Reference and Distance Map of the United States.