Indian Lake is a reservoir in Logan County in western Ohio in the United States. It is approximately 20 mi (32 km) southeast of Lima. It is fed by the north and south forks of the Upper Great Miami River, Cherokee Mans Run, Blackhawk Creek, and Van Horn Creek, and, starting at the bulkhead or "spillway" (located at what is now State Route 366) built in the 1850s by Irish laborers, is the beginning of the Great Miami River.