Willeo Creek is a 6.7-mile-long (10.8 km) stream in the U.S. state of Georgia, and is located in the north-northwestern part of metro Atlanta. It is a significant tributary of the Chattahoochee River, into which it flows at Bull Sluice Lake, just upstream from Morgan Falls Dam and downstream from the Chattahoochee Nature Center. Together, the two streams form nearly all of the county line between Fulton to the east and Cobb to the west.
The long and narrow Gilhams Lake is on the upper portion of the mainline of the creek. There are numerous small and unnamed tributaries, though several of their lakes are named. From north to south (based on where their outflows join the creek), these are Grande Loch, Cochrans Lake, Highland Lake, Mitchell Lake, Lake Charles, Maddox Lake, Clary Lakes, Spring Lake, Bishop Lake, Princeton Lakes, Willow Point Lake, and Lake Jackson. Most of these are on the west side in far east Cobb.