The Walker River is a river in west-central Nevada in the United States, approximately 62 miles (100 km) long. Fed principally by snowmelt from the Sierra Nevada of California, it drains an arid portion of the Great Basin southeast of Reno and flows into the endorheic basin of Walker Lake. The river is an important source of water for irrigation in its course through Nevada; water diversions have reduced its flow such that the level of Walker Lake has fallen 160 feet (49 m) between 1882 and 2010. The river was named for explorer Joseph Reddeford Walker, a mountain man and experienced scout who is known for establishing a segment of the California Trail.

Nevada is a landlocked state in the Western region of the United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the 7th-most extensive, the 32nd-most populous, and the 9th-least densely populated of the U.S. states. Nearly three-quarters of Nevada's people live in Clark County, which contains the Las Vegas–Paradise metropolitan area, including three of the state's four largest incorporated cities. Nevada's capital is Carson City. Las Vegas is the largest city in the state.