Decorah is the largest city in and county seat of Winneshiek County, Iowa, United States. The population was 7,587 at the time of the 2020 cens…Decorah is the largest city in and county seat of Winneshiek County, Iowa, United States. The population was 7,587 at the time of the 2020 census. Decorah is located at the intersection of State Highway 9 and U.S. Route 52. Located within the Driftless Area in northeastern Iowa, Decorah is situated in the bluffs of the Upper Iowa River, which flows through the city. Decorah is a college town, being the home of Luther College. It is known for its Norwegian-American heritage and the corresponding Vesterhiem Norwegian-American Museum.