Karlstad is a city in Kittson County, Minnesota, United States. The population was 710 at the 2020 census. U.S. Route 59 and Minnesot…Karlstad is a city in Kittson County, Minnesota, United States. The population was 710 at the 2020 census. U.S. Route 59 and Minnesota State Highway 11 are two of the main arterial routes in the city. The city's slogan is "The Moose Capital of the North".