Black Mesa (also called
Big Mountain) is an upland mountainous mesa of
Arizona, north-trending in
Navajo County, west and southeast-trending in
Apache County, in the south/southeast. In
Navajo it is called ("Black Mountain") and during
Mexican rule of Arizona it was called
Mesa de las Vacas (
Spanish "
mesa of the cows"). It derives its dark appearance from the numerous seams of
coal which run through it.