Salem
- County:
- Marion County
- County Seat:
- Yes
- Area (mi²):
- 6.991
- State:
- Illinois
Salem is a city located in Marion County, Illinois. Salem has a 2026 population of 7,016. It is also the county seat of Marion County. Salem is currently declining at a rate of -0.6% annually and its population has decreased by -3.55% since the most recent census, which recorded a population of 7,274 in 2020.