Marion County, Indiana

Marion County
Location within the U.S. state of Indiana
Indiana's location within the U.S.
Coordinates: 39°47′N 86°08′W / 39.78°N 86.14°W / 39.78; -86.14
Country United States
State Indiana
FoundedApril 1, 1822
Named afterFrancis Marion
SeatIndianapolis
Largest cityIndianapolis
Area
  Total
403.01 sq mi (1,043.8 km2)
  Land396.30 sq mi (1,026.4 km2)
  Water6.71 sq mi (17.4 km2)
Population
 (2020)
  Total
977,203
  Estimate 
(2023)
968,460
  Density2,400/sq mi (940/km2)
Time zoneUTC−5 (Eastern)
  Summer (DST)UTC−4 (EDT)
Congressional districts6th, 7th
Websitewww.indy.gov/eGov/County
  • Indiana county number 49
  • Most populous county in Indiana
  • Currently only Unigov county in Indiana

Marion County is located in the U.S. state of Indiana. The 2020 United States census reported a population of 977,203, making it the 54th-most populous county in the U.S., the most populous county in the state, and the main population center of the 11-county Indianapolis–Carmel–Greenwood MSA in central Indiana. Indianapolis is the county seat, the state capital, and most populous city. Marion County is consolidated with Indianapolis through an entity known as Unigov.