Clark County is the most populous county in the U.S. state of Nevada with 2,265,461 residents as of the 2020 census. The county is the location of the state's three largest cities, Las Vegas (the county seat), Henderson, and North Las Vegas, as well as the Las Vegas Strip, Nellis Air Force Base, and Hoover Dam. Clark County has 8,061 square miles (20,880 km2) of land area, roughly the size of New Jersey.
Although the county has 70% of Nevada's population making it the 11th-most populous county in the United States, Clark County covers only 7% of Nevada's land mass. Despite having the name Las Vegas as part of their address, over 1 million residents live in unincorporated Clark County, with municipal services provided by the county. The county plays a role much larger than is typical in the US as it has direct jurisdiction over the Las Vegas Strip and such a large population.
Clark County is governed by the Clark County Commission as its partisan, seven member elected body which enacts ordinances and appoints the county manager to administer the ordinances and daily operations of the county. The Las Vegas Metropolitan Police Department (LVMPD) is a city-county law enforcement agency with jurisdiction over all Clark County, resulting from the merger between the city of Las Vegas’ police department and the county sheriff's office.
Originally occupied by the Southern Paiute people and others, the area became part of the Mexican territory of Alta California—then after the Mexican-American War part of the United States—first as part of the New Mexico Territory, and later the Arizona Territory, before becoming part of Nevada as Lincoln County. Clark County was formed from the southern portion of Lincoln on July 1, 1909.