Hailey is a city in and the county seat of Blaine County, in the Wood River Valley of the central part of the U.S. state of Idaho. The population was 9,161 at the 2020 census, up from 7,960 in 2010. Hailey is the site of Friedman Memorial Airport (SUN), the airport for the resort area of Sun Valley/Ketchum, 12 miles (19 km) north. The town of Bellevue is a few miles south. From 1882 to 1895, Hailey was the county seat of now-defunct Alturas County.