Carroll County is a county located in the U.S. state of Iowa. As of the 2020 census, the population was 20,760. Its county seat is Carroll. The county is named in honor of Charles Carroll of Carrollton, signer of the Declaration of Independence.

Carroll is a city in, and the county seat of, Carroll County, Iowa, United States, along the Middle Raccoon River. The population was 10,321 in the 2020 census.