Grandma's Marathon (Grandma's) is an annual road race held each June in Duluth, Minnesota, in the United States. The course runs point-to-point from the city of Two Harbors on Scenic Route 61 and continues along Lake Superior into the city of Duluth. The finish is located in Canal Park, near Grandma's Restaurant, which is next to the highly visible Aerial Lift Bridge.

Two Harbors is a city in and the county seat of Lake County, Minnesota, United States, along the shore of Lake Superior. The population was 3,633 at the 2020 census. Minnesota State Highway 61 serves as a main route in Two Harbors. Gooseberry Falls State Park is 13 miles (21 km) to the northeast. The city is home to a cargo shipping port for mined iron ore.