Ketchum is a city in Blaine County, Idaho, United States. Located in the central part of the state, the population was 3,555 at the 2020 census, up from 2,689 in 2010. Located in the Wood River Valley, Ketchum is adjacent to Sun Valley and the communities share many resources: both sit in the same valley beneath Bald Mountain, with its skiing. The city also draws tourists to its fishing, hiking, trail riding, tennis, shopping, art galleries, and more. The airport for Ketchum, Friedman Memorial Airport, is approximately 15 miles (24 km) south in Hailey.

Blaine County is a county in the U.S. state of Idaho. As of the 2020 United States Census, the population was 24,272. The county seat and largest city is Hailey. It is also home to the Sun Valley ski resort, adjacent to Ketchum.