Decatur is a city located in Illinois. With a 2020 population of 69,974, it is the 17th largest city in Illinois and the 531st largest city in the United States. Decatur is currently declining at a rate of -0.93% annually and its population has decreased by -8.08% since the most recent census, which recorded a population of 76,122 in 2010. Decatur reached it's highest population of 93,939 in 1980. Spanning over 47 miles, Decatur has a population density of 1,653 people per square mile.
The average household income in Decatur is $58,634 with a poverty rate of 21.14%. The median rental costs in recent years comes to $669 per month, and the median house value is $81,800. The median age in Decatur is 40 years, 36.9 years for males, and 42 years for females. For every 100 females there are 87.8 males.