The Olentangy River rises in northern Morrow County in north central Ohio and twists in a generally westerly direction through Galion before turning to the south about 5 miles west of town. It then flows past Waldo before emptying into Delaware Lake. Upon exiting the dam it continues south through Delaware joining the Scioto River in Columbus.

A stretch of the river below the dam, popular with canoeists and kayakers, is central Ohio's only state designated scenic river.