Formed January 1, 1839 (74th county)
Carroll County (15,705), Mount Carroll (1,477), Savanna (2,784)
The red brick and stone courthouse with columns was built in 1858 in the Italianate style. The building was enlarged in 1895. The county was organized on January 1, 1839 as the 74th county. The county was taken from Jo Daviess County with Savanna as the first county seat. Mount Carroll became the county seat in 1843. The courthouse sits on a square at North Main, Market, Clay, and Rapp streets. Illinois State Highway 78 is Clay Street. William T. Miller is the building designer. The grounds feature veteran memorials. Charles Carroll, signer of the Declaration of Independence, provided the inspiration for the county and county seat’s names. He is the source name for the county seat of Greene County as well.
Carroll County government consists of a sheriff, an administrator, an attorney, a coroner, a clerk, a treasurer, and an assessor (executive). It has 9 Board Members (legislative.) Thirteen Circuit Court Judges serve Carroll, Jo Daviess, Lee, Ogle, and Stephenson counties and a court clerk serves Carroll County (judicial.) The county is located in northwest Illinois on the border with Iowa. The Mississippi River forms its western border. Davenport, Iowa is southwest and Rockford, Illinois is northeast of the county. The county center is 2.6 miles Southeast of Mount Carroll. The county is surrounded clockwise by Stephenson, Ogle, and Whiteside counties and Iowa and Jo Daviess County.
The area of the county is 445 square miles. It is 60 out of 102 in the state. It ranks 68 out of 102 in population in the state. It has a density of 35.3 persons per square mile making it 67 out of 102 in the state. Carroll County has 61.7% of its population in its incorporated areas. United States Highway 52 crosses east to west through the county from Ogle County to Iowa. Except for the wandering western river border, the remainder of the county is rectangular. Mount Carroll is slightly west and north of the county’s center. Savanna is located on the northwestern border on the Mississippi River. Mount Carroll is the county seat and Savanna is the largest city. Mount Carroll is 9.4% of the county population while Savanna is 17.7% of the county population. The largest city is pronounced SA-VAN-UH.
Chadwick
Lanark
Milledgeville
Mount Carroll
Savanna
Shannon
Thomson