Sumner is a city in Bremer County, Iowa, United States. The city is located along the county’s eastern border, between Bremer and Fayette counties. The population was 2,021 at the time of the 2020 census. The Bremer County portion of Sumner is part of the Waterloo–Cedar FallsMetropolitan Statistical Area.
The town was established in 1870, and incorporated in 1894. The community is named after American political leader Charles Sumner.
Sumner is home to Life Line Emergency Vehicles, a major manufacturer of ambulances.
According to the United States Census Bureau, the city has a total area of 2.53 square miles (6.55 km2), of which, 2.52 square miles (6.53 km2) is land and 0.01 square miles (0.03 km2) is water.
Sumner is located on Iowa Highway 93.