Wild River State Park is a state park of Minnesota, United States, curving along 18 miles (29 km) of the St. Croix River. This long, narrow park is shaped somewhat like a sideways 'S', with development largely concentrated in the lower third. The remote upper sections flank the mouth of a tributary called the Sunrise River. The park is managed to provide quieter, more nature-oriented recreation as a counterpoint to the busier William O'Brien and Interstate State Parks downstream.