Boone County is bordered on the north by Wisconsin (Rock and Walworth Counties), on the south by DeKalb County, on the east by McHenry County, and on the west by Winnebago County. In 1850, there were eight townships: Belvidere, Benton (previously Fairfield and then Flora), Boone, Bonus, Caledonia, Leroy (previously Beaver), Manchester and Ohio (later renamed as Spring). Poplar Grove township was eventually created from parts of Boone and Caledonia townships.
Boone County is the smallest of the "northern tier" of counties, having an area of only 290 square miles. Before agriculture was introduced, its surface was chiefly rolling prairie. The earliest settlers came from New York and New England, and among them were included MEDKIFF, DUNHAM, CASWELL, CLINE, TOWNER, DOTY and WHITNEY. Later (after the Pottawattomies had evacuated the country), came the SHATTUCK brothers, Maria HOLLENBECK and Mrs. BULLARD, Oliver HALE, Nathaniel CROSBY, Dr. WHITING, H. C. WALKER, and the NEELEY and MAHONEY families.
The first frame house in the county was erected by S. F. DOTY and stood for fifty years in the village of Belvidere on the north side of the Kishwaukee River.