The Grand River is a river in the southwestern portion of the southern peninsula of Michigan, United States, that flows into Lake Michigan's southeastern shore. It is the longest river in Michigan, running 252 miles (406 km) from its headwaters in Hillsdale County on the southern border north to Lansing and west to its mouth on the Lake at Grand Haven. Native Americans who lived along the river before the arrival of the French and British called the river O-wash-ta-nong, meaning "Far-away-water'", because of its length.