Ballenger Creek is a tributary of the Monocacy River located in Frederick County, Maryland. It flows for approximately 10.7 miles (17.2 km) and covers a watershed area of 21.8 square miles (56 km2).
The creek originates on the east slope of Catoctin Mountain, situated about 3 miles (5 km) west of the city of Frederick. From its headwaters, the stream flows roughly southeast toward the Monocacy National Battlefield before reaching its confluence with the Monocacy River, which eventually drains into the Potomac River.