Nestled in the Ozark foothills north of Grand Lake, the Neosho River is a tributary of the Arkansas River that flows south-southwest through northeastern Oklahoma. Neosho is an Osage Indian word meaning “clear and abundant water.” The river runs about 463 miles long, and via the Arkansas, is part of the Mississippi River watershed. Ending at its confluence with Spring River at the Twin Bridges Area at Grand Lake State Park, the waterway is called the Grand River from that point.