John C. Fremont made the first systematic observations of what now is Nevada from 1843-1845. In 1841, settlers journeying to the west coast began crossing the Humboldt Valley and the Forty Mile Desert, a route later followed by the Overland Stage Lines. The Treaty of Guadalupe Hidalgo, which ended the Mexican War, granted the United States territory that included Nevada. Mormons founded the first settlement at Genoa in the Carson Valley in 1849 and established a mission in the Las Vegas Valley in 1855.
Nevada's major period of growth followed discovery of the Comstock Lode at Virginia City in 1858. Between 1860 and 1870, the population jumped from 7,000 to 42,000. In 1861, Nevada Territory separated from Utah Territory. When statehood was granted Nevada on October 31, 1864, President Abraham Lincoln secured the one vote he needed for ratification of the 13th Amendment. The state often is referred to as "battle born." Nevada's nickname, The Silver State, was derived from its Civil War statehood and from the use of Nevada gold and silver bullion by Union forces to obtain credit throughout the war.