Flandrau State Park is located near MN 15 in Brown County on the Cottonwood River.

The section of MN 15 between New Ulm and the Iowa state line was originally Minnesota Constitutional Route 15, dating back to 1920.

However, funding fell short of completing the freeway beyond MN 23 and County Road 75 (CR 75, 2nd Street South).

As a result, it was eventually decided that right-of-way needed to build interchanges would be sold off so the remaining segment of MN 15 across the Mississippi River, connecting to US 10, could be built.

Cloud area will require the highway to be eventually converted to a freeway in the long term (post 2030).