Dinosaur Mountain is a southern sub-summit of the larger, more famous Green Mountain which looms over Boulder, Colorado, and hosts the famous Flatirons. It defines the southern edge of Skunk Canyon and the northern face of Bear Canyon and is connected to Green Mountain by a narrow saddle. Despite this prominent position, Dinosaur Mountain is often hard to make out against the backdrop of Green Mountain. Never-the-less, it is a first-rate summit with stunning views and a very peaceful, other-worldly feel.
The summit block of Dinosaur Mountain with Bear Peak to the south.
Dinosaur Mountain is covered with flatirons, perhaps moreso than any other of the Boulder peaks. Much like Skunk Canyon to the north, these slanted rock strata are arranged in five distinct layers known (from west to east) as Fourth, Third, Second, First and Front. The summit of Dinosaur Mountain is defined by the crest of the Fourth stratum. Other, more famous features include Dinosaur Rock (first), Der Zerkle (first), the Hand and Finger Flatirons (second), Mallory's Cave (second), the Box (second) and the Back Porch (second). The huge Front Porch (in the front stratum) is the huge, low flatiron that can be seen from the Mesa Trail near NCAR.
Mallory's Cave is the main draw for most people to Dinosaur Mountain. It is a shallow cave perched between the Hand and Finger Flatirons (second stratum). It is also home to several species of endangered bats (Townsends Big-eared in particular) and the cave is closed between April 1 and October 1 to leave the bat maternity colonies undisturbed. During the winter, you can hike up to the cave, ascend a short, 3rd-class ramp, and explore to your heart's content.
The summit of Dinosaur Mountain, however, is also a very worthy destination, and one that very few people see. Whichever route you take, the last few hundred feet feature some really wonderful 3rd class scrambling over exotic, weird rock to breathtaking views. The summit itself sits on the crest of the fourth stratum, but the nearby crest of the third, an indistinct flatiron known as Dum, is nearly as tall and poses an interesting scrambling challenge: a huge flat boulder lies balanced perfectly on top of two lower rocks. The question is how to safely get on top of this table. It can be done as a third-class problem, though harder and more exposed possibilities exist. I won't ruin the fun by detailing it here except to say that the most obvious route is not the easiest.
There is also a plentitude of fifth-class climbing routes on Dinosaur from classic 5.easy east-face slab routes to steep roofs and cracks on the west and south faces of many of the flatirons. Several of these flatirons are under seasonal wildlife closures between Feb 1 and August 1 for raptor nesting. See below for more details.
The most convenient trailhead for Dinosaur Mountain is at the National Center for Atmospheric Research (NCAR). Drive west on Table Mesa Drive. Park in one of the numerous parking spots and hike west on the Walter Orr Roberts Interpretive Trail. At the west end of the trail, bear left and down and continue on the NCAR trail. It ascends another short ridge topped with a green water tank and then descends to the Mesa Trail.
An alternate route to the Mesa Trail is from the Bear Canyon trailhead on Bear Mountain Drive. Follow the service road around a small hill and into Bear Canyon. The Mesa Trail joins on the right and leads up to the saddle behind NCAR and the water tank.
No hiking permits are required, but several parts of Dinosaur Mountain are under seasonal wildlife closures
. This does not generally affect the trails, but some of the flatirons and climbing areas are verboten. In particular, Bear Creek Spire, Der Zerkle, the Hand and Finger Flatirons, and the Skunk Canyon ridges on the north side of Dinosaur Mountain are closed between February 1 and August 1 of each year for nesting raptors. In addition, the popular Mallory Cave is gated between April 1 and October 1 each year for nesting Townsends Big-eared bats and several other species. Disturbing the raptors or bats carries heavy fines.
When To Climb
Dinosaur Mountain can be climbed at any time though winter is likely much harder given the amount of scrambling on rock slabs that must be done toward the summit. Certain rocks are closed during parts of the year (see above), but the trails remain open year-round.
There is no camping in the Boulder Open Space and Mountain Parks, nor is any particularly needed. The round-trip hike from NCAR to the summit and back (with plenty of time for playing on the rocks) takes only a few hours.