Is black mesa real

Yes it is real.

The geologic structure, known as Black Mesa is named for a dark layer of volcanic rock and coal and is part of the Colorado Plateau in the Southwestern USA. Parts of this plateau, and various locations on it, called Black Mesa, are found in the four corners region of the Southwest: New Mexico, Arizona, Utah, and Colorado.

Black Mesa, the game, is real also. All you need is a copy of any source engine game on steam (See the link below).