Hidden Valley Hiking Trail

Hidden Valley Hiking Trail – South Mountain

  • Difficulty Level: Moderate
  • Length: 3.5 Miles (roundtrip).
  • Location: Mormon Trailhead (24th St. & Baseline)
    • (From Baseline turn onto 24th St. towards the mountain and you’ll run into the parking lot)

This is definitely the Phoenix hiking trail that has the most unique rock structures. From a naturally formed tunnel, to boulders squeezed so close together, creating a small pathway (known as Fat Man’s Pass), Hidden Valley is a must do hike!

woman standing in narrow passage along Phoenix hiking trail, between two large boulders., known as Fat Man's Pass  on South Mountain in Phoenix, Arizona
Fat Man’s Pass from above; Hidden Valley – South Mountain, Phoenix, Arizona

Getting onto Hidden Valley Hiking Trail

To get onto this trail you need to start at the Mormon Trailhead, on South Mountain which is located at 24th Street and Baseline.

Seeing as how Hidden Valley is located in the middle portion of South Mountain, you need to take Mormon Trail, to National Trail, which then will intersect with Hidden Valley. So really, Hidden Valley itself is a short mile hike at a half mile, however you need to take two other hiking trails to reach it, making the total distance 3.5 (roundtrip).

For this reason, the most direct route is to hike the switchbacks of Mormon Trail until you see the signs for National Trail.  Mormon trail is just a little over a mile and is moderate to difficult. It begins on an incline which won’t let up until you are at the end of the trail.

dirt hiking trail along side of mountain with loose rocks against other side. Saguaro cactus with multiple arms reaching up to blue sky. City of Phoenix down below
Saguaro Cactus along Mormon Hiking Trail on South Mountain, Phoenix, Arizona

At the end of Mormon trail, when it begins to flatten out you’ll notice trail marker indicating that you are now on National Trail. Follow National for about a half mile and you’ll see the sign for Hidden Valley.

Hidden Valley is a Loop Trail

Hidden Valley is a loop trail, that connects itself onto two different spots on National Trail. The first sign you come up to will be to enter Hidden Vallen via the Natural Tunnel. If you pass this sign and continue along National, you’ll see the second sign for Hidden Valley, via Fat Man’s Pass.

It’s up to you, which starting point you want to take. Just be sure to remember that once you have completed Hidden Valley, you need to turn right back onto National, to get back onto Mormon.

For this trail write up, we began at the second sign, via Fat Man’s Pass.

Fat Man’s Pass

Immediately, as you dip down into Hidden Valley, Fat Man’s Pass lies right there greeting hikers. As mentioned above, this unique rock formation is two huge boulders that are almost touching each other, causing a very narrow pathway.

If you’re small enough you may be able to squeeze through. Or if not, you will be able to walk on top one of the boulders and continue on the path below.

two big boulders close to one another, forming a very narrow pathway. Known as Fat Man's Pass, in Phoenix, Arizona
Fat Man’s Pass; located on Hidden Valley Hiking Trail on South Mountain, Phoenix, Arizona
Woman in purple tank top sitting with legs out on a smooth boulder that angles down toward the sandy ground. Known as Fat Man's Pass on South Mountain in Phoenix, Arizona
Fat Man’s Pass – South Mountain, Phoenix, Arizona

Once after Fat Man’s Pass you will continue walking along the path, entering into a wash section. As you continue, more boulders piled up upon each other will emerge from the side of the trail. It seems like a perfect hikers playground. Lot’s of rocks to climb and areas to explore while you continue walking along the path.

sandy hiking trail with brown and black boulders creating jagged appearance against blue sky along Hidden Valley hiking trail, in Phoenix, Arizona - South Mountain
Hidden Valley – South Mountain, Phoenix, Arizona
Man standing on huge black boulder and walking down toward sandy wash along Hidden Valley Hiking Trail, in Phoenix, Arizona
Hiking down big boulders along Hidden Valley hiking trail, South Mountain – Phoenix, Arizona

Hidden Valley’s Natural Tunnel

As you approach the end of Hidden Valley, one last final rock formation is waiting for you. Known as the Natural Tunnel, it is created by two boulders being close enough together to create a hallway to walk through…while another big boulder sits on top, creating a roof.

brown jagged boulders close together forming a pathway of sand with a boulder on top, making this a natural tunnel. Found on Hidden Valley Hiking Trail on South Mountain, Phoenix, Arizona
Natural Tunnel – Hidden Valley, South Mountain – Phoenix, Arizona
brown jagged boulders close together forming a pathway of sand with a boulder on top, making this a natural tunnel. Found on Hidden Valley Hiking Trail on South Mountain, Phoenix, Arizona
View of Natural Tunnel from entering side
brown jagged boulders close together forming a pathway of sand with a boulder on top, making this a natural tunnel. Found on Hidden Valley Hiking Trail on South Mountain, Phoenix, Arizona
Natural Tunnel, exit view

As you step back onto National Trail, turn right and go back down Mormon Trail, the way you came up.

Phoenix Hiking Trail Essentials:

Over 200 hikers a year have accidents along the Phoenix hiking trails. The desert is a beautiful wide open space but with that also comes a bit of danger that all hikers need to be aware of and be prepared for.

To give you the best hiking experience be sure to bring these following essentials with you on your Phoenix hike

  • Water
  • Sunscreen/Sun Protected Clothing
  • Hat
  • Sunglasses
  • Salty Snacks (electrolytes)
  • Durable shoes

Phoenix
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Humidity: 57%
Pressure: 29.89"Hg
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