
Sullivan
- County:
- Sullivan County
- County Seat:
- Yes
- Area (mi²):
- 1.875
- State:
- Indiana
Sullivan is a city located in Sullivan County, Indiana. Sullivan has a 2025 population of 4,199. It is also the county seat of Sullivan County. Sullivan is currently declining at a rate of -0.28% annually and its population has decreased by -1.39% since the most recent census, which recorded a population of 4,258 in 2020.
The average household income in Sullivan is $52,074 with a poverty rate of 20.61%. The median age in Sullivan is 32.9 years: 25.3 years for males, and 35.9 years for females.