Nevada is a state in the Western, Mountain West, and Southwestern regions of the United States. Nevada is the 7th most extensive, the 35th most populous, and the 9th least densely populated of the 50 United States. Nearly three-quarters of Nevada's people live in Clark County, which contains the Las Vegas–Paradise metropolitan area where the state's three largest incorporated cities are located. Nevada's capital is Carson City. Nevada is officially known as the "Silver State" due to the importance of silver to its history and economy. It is also known as the "Battle Born State", because it achieved statehood during the Civil War; as the "Sagebrush State", for the native plant of the same name; and as "Sage hen State". Nevada is largely desert and semiarid, much of it located within the Great Basin. Areas south of the Great Basin are located within the Mojave Desert, while Lake Tahoe and the Sierra Nevada lie on the western edge. Approximately 86% of the state's land is managed by various jurisdictions of the U.S. federal government, both civilian and military. Prior to European contact, Native Americans of the Paiute, Shoshone, and Washoe tribes inhabited the land comprising the modern state. The first Europeans to explore the region originated from Spain. They gave the region the name of Nevada (snowy) due to the snow which covered the mountains at winter. The area formed part of the Viceroyalty of New Spain, becoming part of Mexico when that country gained independence in 1821. The United States acquired the territory in 1848 following its victory in the Mexican-American War, and the area was eventually incorporated as part of Utah Territory in 1850. The discovery of silver at the Comstock Lode in 1859 led to a population boom that became an impetus to the creation of Nevada Territory out of western Utah Territory in 1861. Nevada became the 36th state on October 31, 1864, as the second of two states added to the Union during the Civil War (the first being West Virginia). Nevada has a reputation for its libertarian laws. With a population of just over 40,000 people, Nevada was by far the least populated state in 1900, with less than half the population of the next least-populated state. However, the establishment of legalized gambling and the adoption of lenient marriage and divorce proceedings in the 20th century transformed Nevada into a major tourist destination. Nevada is the only U.S. state where prostitution is legal, though it is illegal in Clark County and in Washoe County, which contain Las Vegas and Reno, respectively. The tourism industry remains Nevada's largest employer, with mining continuing as a substantial sector of the economy: Nevada is the fourth-largest producer of gold in the world.