The Ottawa River is a short tributary that empties into the North Maumee Bay (Lake Erie) less than one mile north of the Ohio-Michigan state line and only 2.3 miles north of the Maumee River mouth. With the exception of the mouth and the river’s first three-quarters of a mile, the 20-mile Ottawa River flows within Lucas County. The river begins at the confluence of the Ten Mile and North Ten Mile creeks in Sylvania. The North Ten Mile Creek is a 4-mile tributary that originates in Michigan. The 27-mile long Ten Mile Creek flows entirely within Ohio, although it meanders within 160 feet of the state line. The Ottawa River Watershed is 220.9 square miles and drains portions of Fulton and Lucas counties in Ohio and portions of Lenawee and Monroe counties in Michigan.

The Ottawa River is named after the Ottawa Indians, a Native American tribe that once inhabited the area. ‘Ottawa’ is an anglicized spelling of the word ‘adawe,’ which means “trader” or “to trade.” The river also shares its name with another western Lake Erie Watershed tributary. The other Ottawa River is a 50-mile tributary that rises in Hardin County, flows through Allen and Putnam counties and empties into the Auglaize River, which then flows into the Maumee River.