Father Kino expeditions at the end of the 17th century through north Mexico and south U.S., Nevada passed to Spanish control, belonging to the Viceroyalty of New Spain. In 1821, it became part of the First Mexican Empire of Agustin de Iturbide, until 1823, and afterwards of the Mexican Republic. As a result of the Mexican-American War of 1846-48 and based on the Guadalupe-Hidalgo Treaty, Nevada became part of the United States. On August 14, 1850, the U.S. Congress established the Utah territory which included the present day state. 1859 saw the discovery of the Comstock Lode, a rich outcropping of gold and silver, and the mining center Virginia City sprang up. This discovery brought a flood of miners, prospectors, merchants and others hoping to strike it rich.
On March 2, 1861, the Nevada Territory separated from the Utah territory and adopted its current name, shortened from Sierra Nevada (Spanish for "snowy range"). Eight days prior to the presidential election of 1864, Nevada became the 36th state in the union. Statehood was rushed to the date of October 31 - coincidentally Halloween - to help ensure Abraham Lincoln's reelection and post-Civil War Republican dominance in Congress.  As Nevada's mining-based economy tied it to the more industrialized Union, it was viewed as more politically reliable than other Confederate-sympathizing states such as neighboring California. It is a common misconception that one of the reasons Nevada was granted statehood was its large deposits of silver and gold. This is merely a myth, however, and would have been illogical in that Congress had unlimited control over these resources when Nevada was a territory and only limited control after Nevada became a state.
Nevada achieved its current boundaries on May 5, 1866 when it absorbed the portion of Pah-Ute County in the Arizona Territory west of the Colorado River, essentially all of present day Nevada south of the 37th parallel. The transfer was prompted by the discovery of gold in the area, and it was thought by officials that Nevada would be better able to oversee the expected population boom. This area includes most of what is now Clark County.
Mining shaped Nevada's economy for many years (see Silver mining in Nevada). However in the late 19th century, Nevada found it increasingly more difficult to compete with states such as Colorado and Utah in the mining industry. There was even talk of stripping away statehood, the only time in American history such an action was discussed in Congress. However, the rich silver strike at Tonopah in 1900 is thought to have saved the state from near collapse. This was followed by strikes in Goldfield and Rhyolite, lasting well into the 1910s and making Nevada a dominant player in mining once again.