Fortification Hill is a prominence adjacent Lake Mead in the Lake Mead National Recreation Area; it is located at the northwest terminus region of the Black Mountains (Arizona), and specifically the north region of the Black Mountains. It is near a southern section of Lake Mead, and just northeast of Hoover Dam. It can easily be seen eastward across Las Vegas Bay or from the two northern mountain terminuses of Eldorado Mountains (Nevada), or the Black Mountains (Arizona). The flat mountaintop, sloping northwards is composed of Tertiary basaltic lava flows.