Tazewell County, Illinois: History
Tazewell County was formed out of Peoria County in 1827. The consensus appears to be that it was named in honor of Littleton Tazewell, who served in the U.S. Senate, and who became Governor of Virginia in 1834. It is, however, possible that it was named after Littleton's father, prominent Virginia politician Henry Tazewell, after whom Tazewell County, Virginia, was named.
The first county seat was in Mackinaw from 1827 to 1836. It was moved temporarily from Mackinaw to Pekin in June 1831, with the county court proceedings in the Snell schoolhouse. It moved to Tremont in 1836. After a political struggle between Tremont and Pekin, the county seat was reassigned to Pekin in 1849.