Marion is a city located in Illinois. With a 2020 population of 17,502, it is the 145th largest city in Illinois and the 2061st largest city in the United States. Marion is currently declining at a rate of -0.34% annually but its population has increased by 1.80% since the most recent census, which recorded a population of 17,193 in 2010. Marion reached it's highest population of 17,746 in 2013. Spanning over 17 miles, Marion has a population density of 1,059 people per square mile.
The average household income in Marion is $60,602 with a poverty rate of 19.70%. The median rental costs in recent years comes to $713 per month, and the median house value is $117,800. The median age in Marion is 39.2 years, 36.5 years for males, and 42 years for females. For every 100 females there are 92.8 males.