Washington is a city in Tazewell County, Illinois, United States. Washington is on U.S. Route 24 and Illinois Route 8, northeast of East Peoria. The population was 16,071 at the 2020 census, a 48.2% percent increase over 2000. It is a suburb of Peoria and is part of the Peoria Metropolitan Statistical Area.

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."