Anza-Borrego Calcite Mine Slot Canyon

The Calcite Mine is an unexpected hidden gem (pun intended!) in the Anza Borrego Wilderness near San Diego. This relatively unknown hike features an epic slot canyon, sweeping desert views, and fascinating history. Not to mention the trip to the trailhead requires some exciting off-roading and the canyon itself holds several technical obstacles.

Keep your eyes out for calcite crystals on this hike. This area was mined for calcite during World War II to fabricate Norden bombsights. The mining operation has since been abandoned but hikers may spot vestiges from decades ago.

I’ll start off this trail description by saying that we almost certainly did not take the correct route! There are lots of side trails and off-trail options and we ended up doing a long loop through the canyon and up a mountain adjacent to the parking lot. I would estimate that it was about 5 miles over all. The map I show on this page is also my best guess as to the route we took on legs outside of the slot canyon.

We started southeast from the parking area on the most prominent looking trail and ended up on a large hill with panoramic views of the whole area. This helped set our bearings and locate the slot canyon. We returned part of the way back down the hill and then veered east towards the most gradual looking slope towards the canyon. Before that we took a wrong turn and found ourselves too high above the slot canyon to get down to it.

This trail wound around and merged with the main slot canyon. We headed north up the canyon which quickly closed in around us. We passed through a variety of rock formation – smooth walls, swiss-cheese looking stones, and carefully balanced boulders. We reached a number of technical obstacles that already had some ropes in place. Using the ropes and boosts/hands from friends we didn’t have much trouble climbing them.

After some time, the slot canyon started to open up and we were in more of a valley. Honestly, at this point we weren’t entirely sure where we were so we started hiking off-trail up a large hill to our west which seemed to be in the direction of the car. Fortunately, after a grueling hike to the top we were met with a birds-eye view of the trail, road, and parking area! We chose a gradual path back down and made it back to the cars!

This hike is somewhat dog-friendly for those that like hiking and can scramble over stones. As I mentioned above there are several obstacles where you have to use ropes and do some bouldering. We have a smaller dog so we were able to pick her up and pass her over the obstacles (her harness helped). I’m not sure how this could be done with a larger dog.

Season

We hiked this loop towards the end of March and it was very hot and dry! This is a desert so make sure to bring tons of water, sunscreen, hats, and other sun protection. Always avoid slot canyons if there are any signs of rain, dangerous flash flooding can occur.

getting there

This trailhead is located in the Anza-Borrego Wilderness. Turn north off the Borrego Salton Seaway onto Calcite Road.

Fortunately, I went on this trip with friends who were well prepared for off-roading! To start at the actual trailhead, you'll need a high-clearance 4WD vehicle as well as some confidence to navigate over large boulders and through narrow passages. Otherwise you can hike an extra 2 miles each way from the main road. If you hike up the off-road section, it looks like there are options to enter the slot canyon closer to where it actually starts. As I mention above the trail we took merged in the middle of the canyon.

There are no permits or fees required for this hike.

Updated May 2016