Northern Sky Theater is a professional theater company that creates, develops and produces musicals based on the populist culture and heritage of the United States. Located in Door County, Wisconsin, the company began in 1970 as The Heritage Ensemble, performing on the stage of the 700-seat outdoor theater in Peninsula State Park. In 1990, American Folklore Theatre was co-founded by Fred Alley, Frederick Heide and Gerald Pelrine. In 2015, the company changed its name to Northern Sky Theater.

Peninsula State Park is a 3,776-acre (1,528 ha) Wisconsin state park with eight miles (13 km) of Green Bay shoreline in Door County. Peninsula is the third largest state park in Wisconsin and is visited by an estimated one million visitors annually.