Marion is a city in Linn County, Iowa, United States. The population was 26,294 at the 2000 census and was 41,535 in 2020, an increase of 58%. The city is located next to Cedar Rapids and part of the Cedar Rapids Metropolitan Statistical Area.

Linn County is a county located in the U.S. state of Iowa. As of the 2020 census, the population was 230,299, making it the second-most populous county in Iowa. The county seat is Cedar Rapids. Linn County is named in honor of Senator Lewis F. Linn of Missouri. Linn County is included in the Cedar Rapids, IA Metropolitan Statistical Area.