Greenville Saltpeter Cave is a non-commercial "wild" cave in Monroe County. It has 3.8 miles of twisting passages and four entrances.

The cave is named for its historical role in manufacturing saltpeter (potassium nitrate), an essential ingredient for gunpowder. It was mined for this purpose during the Civil War and earlier in the 1800s.

The cave is along the route of Laurel Creek, which sinks into the ground a mile north of Greenville and reemerges from the cave's main entrance near a mill pond. It was designated a National Natural Landmark in 1973 and was acquired by the West Virginia Land Trust to be protected as a preserve.

The cave is critical for several species of endangered bats, including the Indiana bat and northern long-eared bat. The cave is especially important because it houses one of the largest surviving groups of tricolored bats anywhere.

Note: This is a wild cave on private property and is not open to the general public due to safety and the need to protect its natural resources and endangered animals.