Carroll is a city in and the county seat of Carroll County, Iowa, United States, located along the Middle Raccoon River. The population was 10,103 in the 2010 census, a decline of 3 people from the 10,106 population in the 2000 census.
Carroll County is named in honor of Charles Carroll of Carrollton, Maryland. He was the only Roman Catholic to sign the Declaration of Independence, and the longest living signatory.
In 1855 a county government was set up in the town of Carrollton. Three years later a courthouse was constructed at a cost of approximately $3,000. Construction was begun by Nelson Moore, but he died with only one floor completed. The second story was completed by L. J. Hampton.