Bannock County is a county in the southeastern part of Idaho. As of the 2020 census, the population was 87,018, making it the sixth-most populous county in Idaho. The county seat and largest city is Pocatello. The county was established in 1893 and named after the local Bannock tribe. It is one of the counties with territories included in the Fort Hall Indian Reservation of the federally recognized Shoshone-Bannock Tribes.

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.