Geary County is a county located in the U.S. state of Kansas. Its county seat and most populous city is Junction City. As of the 2020 census, the county population was 36,739. The county is named in honor of John Geary, the first mayor of San Francisco, a governor of the Kansas Territory, and the 16th governor of Pennsylvania.

Junction City is a city in and the county seat of Geary County, Kansas, United States. As of the 2020 census, the population of the city was 22,932. Fort Riley, a major U.S. Army post, is nearby.