Pocatello ( ) is the county seat and largest city of Bannock County, with a small portion on the Fort Hall Indian Reservation in neighboring Power County, in the southeastern part of the U.S. state of Idaho. It is the principal city of the Pocatello metropolitan area, which encompasses all of Bannock County. As of the 2020 census, the population of Pocatello was 56,326. Pocatello is the 6th most populous city in the state, just behind Caldwell. The city is at an elevation of 4,462 feet (1.360 km) above sea level and it sits on the Portneuf River in the Snake River Plain ecoregion. Pocatello covers a land area of 33.36 square miles (86.4 square kilometers). Pocatello is the home of Idaho State University and the manufacturing facility of ON Semiconductor Corporation, and is served by the Pocatello Regional Airport.