Carroll County is named for Charles Carroll, who was a signer of the Declaration of Independence and who resided in Carrollton.
Surrounding County Courthouses:
N – Jo Daviess County and Stephenson County
E – Ogle County
S – Whiteside County
W – Clinton County, Iowa and Jackson County, Iowa
Created: February 22, 1839 
County Seat:
Savanna 1839 – 1843
Mount Carroll 1843 – present
County Courthouse – Mount Carroll
Location: 301 North Main Street / East Market Street
Built: 1856 – 1858
Style: Italianate
Architect: William B Olmsted and Peter A Nicholson of Chicago
Contractor: Locan labor
Description: The building faces west and is a two story red colored brick and stone structure. The building is located on landscaped grounds in the center of Mount Carroll on the north side of the Courthouse Complex which has the County Courthouse Annex on the iouth side and a building with portico in the center. The foundation is constructed of course stone. The upper windows are arched and the roof is hipped. In the interior are wooden stairs and wood trim. The courtroom is located on the second story. The building houses the County Circuit Court of the 15th Judicial Circuit. On the south side is a two story red colored brick building with a large portico on the west front supported by four large white columns constructed in 1958.
Note: The courthouse was repaired and completed in 1858 to 1860 by William T Miller and Jacob P Emmert with stone mason James Watson and brick layers James Hallet and B H Hallet.
County Courthouse Annex – Mount Carroll
Location: 301 North Main Street / East Market Street
Built: 1895
Style: Italianate
Architect: George O Garney
Contractor: Unknown
Description: The building faces west and is a two story red colored brick and stone structure. The building faces west and was completed in 1895. The building is located on landscaped grounds in the center of Mount Carroll on the south side of the Courthouse Complex. The building has an arched entrance topped by a slanted stone roof. The base of the building is course stone. Horizontal bands of light stone divide the floors and edge the windows.
See: The 15th Judicial Circuit includes Jo Daviess County, Lee County, Ogle County and Stephenson County.
History: The county was created in 1839 and Savanna was selected as the county seat. In 1843, the county seat was moved to Mount Carroll. The county rented premises until the first and present courthouse was constructed in 1856 to 1860 at a cost of $30,500.
County Courthouse – north section – Mount Caroll
County Courthouse – middle section - Mount Caroll
County Courthouse Annex – south section - Mount Caroll
Photos taken 2007