Sponsored Topics. Rockwell City is a city in Calhoun County, Iowa, United States. The population was 2,264 at the 2000 census. It is the county seat of Calhoun County. Rockwell City is located at 42°23′45″N 94°37′59″W / 42.39583°N 94.63306°W / 42.39583; -94.63306 (42.395906, -94.632946).