Grinnell is a city in Poweshiek County, Iowa, United States. The population was 9,564 at the time of the 2020 census. It is best known for being the home of Grinnell College, as well as being the location of the Merchants' National Bank building, designed by famous architect Louis Sullivan.

Poweshiek County is a county in the southeastern part of the U.S. state of Iowa. As of the 2020 census, the population was 18,662. The county seat is Montezuma. The county is named for the chief of the Fox tribe who signed the treaty ending the Black Hawk War. It lies along Interstate 80 between Des Moines and Iowa City. Poweshiek County's largest city is Grinnell.