Ballenger Creek is a 10.7-mile-long (17.2 km) tributary of the Monocacy River in Frederick County, Maryland. The headwaters of the creek are located on the east slope of Catoctin Mountain, about 3 miles (5 km) west of the city of Frederick. The stream runs roughly southeast to the Monocacy National Battlefield and the confluence with the Monocacy River, which drains to the Potomac River.