Fairfield is a city located in Wayne County Illinois. It is also the county seat of Wayne County. With a 2020 population of 4,858, it is the 336th largest city in Illinois and the 4845th largest city in the United States . Fairfield is currently declining at a rate of -0.80% annually and its population has decreased by -5.74% since the most recent census, which recorded a population of 5,154 in 2010. Fairfield reached it's highest population of 6,362 in 1960. Spanning over 4 miles, Fairfield has a population density of 1,205 people per square mile.
The average household income in Fairfield is $49,227 with a poverty rate of 21.23%. The median rental costs in recent years comes to $622 per month, and the median house value is $74,800. The median age in Fairfield is 43.1 years, 40.3 years for males, and 44.9 years for females.