Tazewell County is a county in the U.S. state of Illinois. According to the 2020 census, it had a population of 131,343. Its county seat and largest city is Pekin. It is pronounced with a short "a", to rhyme with "razz" rather than "raze."

Pekin is a city in and the county seat of Tazewell County in the U.S. state of Illinois. Located on the Illinois River, Pekin is the largest city of Tazewell County and the second most populous municipality of the Peoria metropolitan area, after Peoria itself. As of the 2020 census, its population is 31,731. A small portion of the city limits extend into Peoria County. It is a suburb of Peoria and is part of the Peoria Metropolitan Statistical Area.