Eureka is a city located in Woodford County Illinois. With a 2020 population of 5,247, it is the 323rd largest city in Illinois and the 4645th largest city in the United States . Eureka is currently declining at a rate of -0.34% annually and its population has decreased by -0.91% since the most recent census, which recorded a population of 5,295 in 2010. Eureka reached it's highest population of 5,383 in 2011. Spanning over 3 miles, Eureka has a population density of 1,955 people per square mile.
The average household income in Eureka is $71,915 with a poverty rate of 15.64%. The median rental costs in recent years comes to $599 per month, and the median house value is $140,000. The median age in Eureka is 34.5 years, 33 years for males, and 36.9 years for females.