Marion is a city in Marion County, Ohio, United States, and its county seat. It is located in north-central Ohio, approximately 50 miles (80 km) north of Columbus. The population was 35,999 at the 2020 census, down slightly from 36,837 at the 2010 census. It is the largest city in Marion County and the principal city of the Marion micropolitan area. It is also part of the larger Columbus–Marion–Zanesville, OH Combined Statistical Area.
President Warren G. Harding, a former owner of the Marion Star, was a resident of Marion for much of his adult life and is buried at Harding Tomb. The city and its development were closely related to industrialist Edward Huber and his extensive business interests. The city is home to several historic properties, some listed on the National Register of Historic Places listings in Marion County, Ohio.