The Boardman River (/bɔːrdmən/ BORD-mən), also known as the Ottaway River or the Boardman–Ottaway River, is a 28.2-mile-long (45.4 km) river in the northwestern Lower Peninsula of Michigan. It rises in western Kalkaska County, and flows west and north through Grand Traverse County to end in downtown Traverse City at the Grand Traverse Bay, a bay of Lake Michigan. The river's watershed drains an area of 295 square miles (760 km2) through a combined 130 miles (210 km) of river and tributaries. Additionally, the Boardman River is considered one of the top ten trout streams in Michigan.