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. An indigenous name for the river was Gininwabiho-zibi, meaning "War Eagle Iron River." The river's lower course flows through Split Rock Lighthouse State Park, and the Superior Hiking Trail ascends and descends both banks.