Sullivan is a city located in Indiana. With a 2020 population of 4,087, it is the 139th largest city in Indiana and the 5338th largest city in the United States. Sullivan is currently declining at a rate of -0.12% annually and its population has decreased by -3.81% since the most recent census, which recorded a population of 4,249 in 2010. Sullivan reached it's highest population of 5,423 in 1950. Spanning over 2 miles, Sullivan has a population density of 2,179 people per square mile.
The average household income in Sullivan is $45,533 with a poverty rate of 16.84%. The median rental costs in recent years comes to $625 per month, and the median house value is $76,300. The median age in Sullivan is 43.9 years, 39.5 years for males, and 52.2 years for females. For every 100 females there are 116.1 males.