Third Hill Mountain is both the highest and most topographically prominent mountain in Berkeley County within the Eastern Panhandle of West Virginia. Third Hill Mountain reaches its highest elevation of 2165 ft above sea-level southeast of the "Locks-of-the-Mountain" where it "locks" with Sleepy Creek Mountain. The long distance Tuscarora Trail passes along ridge and bench of the mountain.

Adjacent area

Together with Sleepy Creek Mountain, the two mountains contain between them Sleepy Creek Lake and the Sleepy Creek Wildlife Management Area. Sleepy Creek and Third Hill Mountains are distinctive for their height in the relatively level terrain of the far Eastern Panhandle region of West Virginia.