The Frenchman Mountains (sometimes referred as the Sunrise Mountains) rise majestically 2,000 feet above the east side of Las Vegas. They reside in the area, known locally, as Sunrise Manor. Frenchman Mountain, often mistaken as Sunrise Mountain, is the highpoint. There is, however, a Sunrise Mountain in this range. One can see the sun greet Las Vegas each morning over this range.
The Frenchman Mountains started to form nearly 1.7 billion years ago. This was during the Precambrian Era. The rocks here are the oldest rocks in the Lake Mead area. They are known as "Vishnu Basement Rocks." These rocks are metamorphic in nature, found primarily in the Lake Mead and Grand Canyon region.
There is also a cave in the Frenchman Mountain Region. Gypsum Cave, which is 300 feet long by 120 feet wide, was once thought to be an aboriginal site. Many neat artifacts can be found at this cave. It is located on the east end of the range. This is also the largest Gypsum Cave in the world.
From I-15 in Las Vegas, exit at Lake Mead Blvd East (Exit 45B). Drive approximately 8.2 miles to the East up to the pass between Sunrise and Frenchman. There is a parking area on the right (south side of the road). This is by the service road that goes up Frechman Mtn.
Alternatively one could park at the Albertsons at 6885 E Lake Mead Blvd, just east of Hollywood along Lake Mead BLVD, and hike from here. This would be good if one is more concerned about their vehicle being broken into so it is in a more popluated area. Break-ins have been known off the road in this area.
There are some 4WD roads in the area but these roads have been closed to motor vehicles. Be aware of people that go on these roads to dump!
For routes hiking Frenchman Mountain, one can also hike from the Mormon Temple. Refer to routes for alternative ways to summit Frenchman Mountain. The views of Las Vegas and Lake Mead are well worth the trip. For great closer views of Nellis AFB hike Sunrise Mountain.
Hiking is fine in this area. Be sure not to wonder on Nellis AFB Area 2 on the north side of Sunrise Mountain though. Don't be tempted to drive on the 4WD roads near here. They are closed to motor vehicles. The BLM around Las Vegas is cracking down on this. Watch for people dumping around here too.
For more information contact:
Bureau of Land Management
Las Vegas Field Office
4701 North Torrey Pines Drive
Las Vegas, Nevada 89130
"The Frenchman Mountains were formed nearly 2 billion years ago."
There are preCambrian basement rocks exposed, but the mountains themselves are Paleozoics not more than 540 million years old. More important, the limestones were thrust to the present position MUCH later -- perhaps less than 17 million years ago.
I heartily recommend the book "Geologic Tours in the Las Vegas Area" (Expanded edition) by the NV Bur. Mines and Geol., special pub 16 (2001, Mackay School of Mines). You will find this book in many local bookstores in the "local section", and it was sold at the RR visitor center at one time. Principal author is J.V.Tingley.
You shouldn't have to resort to the internet, but the book can be obtained...