The Split Rock River is a 3.5-mile-long (5.6 km) river of Minnesota, in the United States. It drains a small watershed of about 40 square miles (100 km2) on the North Shore of Lake Superior. The name was used as early as 1825 and is believed to refer either to the steep-walled gorge carved by the river or to two cliffs east of the river mouth that appear split apart.