Walnut is a city in Pottawattamie County, Iowa, United States. The population was 747 at the time of the 2020 census. Walnut is located on Interstate 80 and is famous for its many antique stores. In recent years Walnut has become a regional center of wind turbine electrical generation.

Pottawattamie County is a county located in the U.S. state of Iowa. At the 2020 census, the population was 93,667, making it the tenth-most populous county in Iowa. The county takes its name from the Potawatomi Native American tribe. The county seat is Council Bluffs.