Some of the cities, towns, and places in Grundy County are Beaman, Beaver Township, Black Hawk Township, Clay Township, Colfax Township, Conrad, Dike, Fairfield Township, Felix Township, German Township, Grant Township, Grundy Center, Holland, Lincoln Township, Melrose Township, Morrison, Palermo Township, Pleasant Valley Township, Reinbeck, Shiloh Township, Stout, Washington Township, Wellsburg

Grundy County is a county located in the U.S. state of Iowa. At the 2020 census, the population was 12,329. The county seat is Grundy Center. The county is named for Felix Grundy, former U.S. Attorney General.
Grundy County is included in the Waterloo-Cedar Falls metropolitan area.