Boise is the capital and most populous city of the U.S. state of Idaho. The population was 235,685 at the 2020 census. The Boise metropolitan area, also known as the Treasure Valley, includes five counties with an estimated population of 846,000, the most populous metropolitan area in Idaho and 74th-most populous in the United States. Located on the Boise River in southwestern Idaho, it is 41 miles (66 km) east of the Oregon border and 110 miles (177 km) north of the Nevada border. Downtown Boise's elevation is 2,704 feet (824 m) above sea level. It is the county seat of Ada County.