Eureka is a city in Woodford County, Illinois, United States. The population was 4,871 at the 2000 census. It is the county seat of Woodford County. The city was founded in the year 1855. Eureka is part of the Peoria-Pekin MSA. Eureka apartments for rent comparison page shows most up to date rent information on Eureka apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.