Illinois Regional Archives Depository (IRAD) System Illinois State Archives
Carroll County Courthouse
301 N. Main St.
Mt. Carroll, IL 61053
815-244-0221 – County Clerk
815-244-0230 – Circuit Clerk
815-244-0223 – Recorder
Regional History Center
Founders Memorial Library
Northern Illinois University
DeKalb, IL 60115
- February 22, 1839 (Laws, 1839, p. 160)
Origin of the name of the county
- Named for Charles Carroll of Carrollton, Illinois, a statesman of the American Revolutionary period, signer of the Declaration of Independence, and United States Senator from Maryland.
Present area, or parts of it, formerly included in
- 1827–1839 – JoDaviess
- 1825–1827 – Putnam
- 1825–1827 – Henry
- 1823–1825 – Fulton
- 1821–1823 – Pike
- 1812–1821 – Madison
- 1795–1812 – St. Clair
- 1839–1843 – Savanna
- 1843–present – Mt. Carroll
History of county governing board
- 1839–1850 – County Commissioners’ Court
- 1850–present – County Board of Supervisors
- Adopted – November 6, 1849
- Cherry Grove – Originally included the area of Shannon (first designated Lost Grove) as a temporary attachment.
- Elkhorn Grove
- Fairhaven – Formed from territories originally attached to Harlem (York) and Wysox (date unknown).
- Lima – Originally included the east half of Rock Creek as a temporary attachment.
- Mt. Carroll
- Rock Creek – The west half of township was originally attached temporarily to Rosehall (Salem) and the east half to Lima (date of uniting two halves unknown).
- Salem – Name changed from Rosehall (date unknown); originally included west half of Rock Creek as a temporary attachment.
- Savanna – Originally included as temporary attachments an area called Rush Creek (eastern part of Washington) and an area called Portsmouth (western part of Washington).
- Shannon – Formed from territory originally designated Lost Grove and attached temporarily to Cherry Grove (date unknown).
- Washington – Created from territories originally designated Portsmouth (western part) and Rush Creek (eastern part) and attached temporarily to Savanna (date unknown).
- Wysox – Originally included southeast part of Fairhaven as a temporary attachment.
- York – Name changed from Harlem (date unknown); originally included much of Fairhaven as a temporary attachment; western part, originally designated Bluffville, was also included as a temporary attachment that later became permanent.