Junction City is a village in Madison County, Missouri, United States. The population was 283 at the 2020 census, down from 327 in 2010. Junction City is in northeastern Madison County, bordered to the south by Fredericktown, the county seat. Missouri Route 72 passes through the village, leading west 2 miles to U.S. Route 67 and east 40 miles to Ja…Junction City is a village in Madison County, Missouri, United States. The population was 283 at the 2020 census, down from 327 in 2010. Junction City is in northeastern Madison County, bordered to the south by Fredericktown, the county seat. Missouri Route 72 passes through the village, leading west 2 miles to U.S. Route 67 and east 40 miles to Jackson. State Highway OO leads north from Junction City 18 miles to Farmington.