Pets allowed
Allowed with Restrictions
Elevation Gain
1,007.00 ft (306.93 m)
Trail type
3.50 mi (5.63 km)
Please respect the outdoors by practicing Leave No Trace. Learn more about how to apply the principles of Leave No Trace on your next outdoor adventure here.

One of the most popular places to start a hike near Boulder is the National Center for Atmospheric Research, or NCAR. This research center is fully funded from the National Science Foundation, other U.S. government agencies, other national governments, and the private sector. Besides offering public tours and exciting field trip opportunities for youngsters, the huge parking lot and proximity to trails in the foothills makes this a fantastic place to do close-to-home hiking and running. One of the more interesting hikes in the area is to Mallory Cave, which sits about 1,000 feet above NCAR tucked away among great rock climbing slabs.

While the trail is open year round and the view from the cave is pretty spectacular, the cave itself has been closed permanently to the public due to White-Nose Syndrome, which has caused the death of millions of bats in North America since it was discovered in 2006. That said, the gate to the cave is interesting to see, along with information panels on the way, the quiet forest, and the great views of the Boulder Valley. It is worth noting that the final 100 feet of the trail is more of a scramble than a hike and should be done only in dry conditions.

Starting from NCAR, take the Walter Orr Roberts Nature Trail toward the mountains. At the top of a short climb is an abandoned water tank; keep to the left and continue down the other side. From the first signed intersection keep left, and almost immediately you’ll come to a four-way stop. Go straight through it to keep on the Mallory Cave Trail. From this point the hike will get much less crowded as the Mallory Cave Trail ends at Mallory Cave. Several rock climbing access points are on the trail, so keep an eye out for outdoor climbers. Near the top of the trail there are a few open areas with views of NCAR, Boulder, and into the plains beyond. For those not doing the scramble, this will be the best spot for photographs.

From the end of the trail, it can be tricky to know where to go up to the cave, find the plaque in the rock, and follow the indent up toward a hole nestled in some fallen rocks. You may need to take your backpack off to squeeze through, and larger adults may find it difficult to make it all the way to the cave. Always play it safe and don’t try to do anything that will cause an injury as the rock up there is quite slippery, even in dry conditions. On the other side of the gap you’ll see the Mallory Cave gate to the right and a pretty wide open view to the left. Go back the way you came once you’re done. There are several looping options once you get back to the Mesa Trail if you want to extend it slightly back to the NCAR.

Logistics + Planning

Preferable season(s)




Parking Pass


Open Year-round



Lower traffic. Interesting cave. Plains views.


Cave closed to public.

Trailhead Elevation

6,076.00 ft (1,851.96 m)

Highest point

6,827.00 ft (2,080.87 m)


Big vistas
Family friendly

Typically multi-day


Permit required



Nearby Lodging + Camping


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