Waterloo is a city in and the county seat of Black Hawk County, Iowa, United States. It is the eighth-most populous city in Iowa, with a population of 67,314 at the 2020 census. Waterloo comprises a twin conurbation with neighboring municipality Cedar Falls. The Waterloo – Cedar Falls metropolitan area has an estimated 170,000 residents.
Waterloo is a major manufacturing, commercial, and cultural center in Northeast Iowa. Known as the “Factory City,” John Deere brand agricultural machinery has been produced in the city for over a century. Waterloo is bisected by the Cedar River flowing to the Southeast.