I love recommending Devil's Backbone Open Space to families and visitors. The highlight of the trail is walking along a rocky ridgeline with several arches.
The trailhead for Devil's Backbone Open Space is just a few miles west of Loveland (directions below). One warning though, the trailhead is very popular with locals, so it often fills up on weekends, even in winter.
At the trailhead, pick up a map and start down a short hill to a picnic area in the trees. Pass the picnic area and hike the rocky, dirt trail in a valley between two ridges. Quickly you'll come to two bridges, this is a good spot to teach the kids about the importance of reading the signs. The bridges here are for pedestrians only. Bikers and equestrians are asked to go around. There are more trails ahead where only foot traffic is welcome.
About 0.4 miles from the trailhead, visitors come to a bench with a view and a trail split. This is a nice spot to sit and pull out the water. However, if you have the energy, I suggest going just a little bit further. This is the first trail split where foot traffic goes left and bikes and horses (and pedestrians, if they want) go right. Go left!
You're now on the Keyhole Trail. Just a few steps from the trail split you'll see why I said it's worth going a little further before you take a break. Take a look at the impressive, rocky ridgeline here. This vertical wall is made of Dakota Sandstone.
As you walk the Keyhole Trail, you may notice several arches or openings in the vertical wall. Some are small enough to see light through them, but at least two appear to be pretty big.
About 0.75 miles from the trailhead, there's a trail split and a sign explaining that Medina Mariano claimed to be the first modern settler in the valley. In 1858, he was charging people for a ferry ride across the Big Thompson River. The Overland Trail used Mariano Crossing as a post in 1862.
A short trail here leads up a hill to an outlook with two benches and a sign pointing out all of the peaks in the distance. On a clear day you can see Longs Peak and at least 3-13ers (13ers are mountains over 13,000 feet in elevation).
After enjoying the view and taking a break on the benches, it's time to head for the highlight of this hike -- the keyhole.
It's about another quarter mile of hiking to the next trail split of the Keyhole Trail and the Bypass Trail. Take the Keyhole Trail just a short distance to the large opening. The "Keyhole" is more than 20 feet high, according to Larimer County officials. There are two benches here, so visitors can take a break and enjoy the view of the mountains through the keyhole.
When you've taken in your fill, it's decision time.
- You can return the way you came for a hike of about two miles roundtrip (and 350 feet of elevation gain with all the ups and downs).
- You can make a short loop by hiking north to the end of the Bypass Trail and turning back there. (Still about two miles roundtrip.)
- Or for a different view, hike north to the end of the Keyhole Trail where it meets the Wild Trail in the valley. Turn south/right here and take the Wild Trail back to the parking lot for a loop hike of 2.4 miles. As you hike the Wild Trail, you'll still see the ridgeline and get a different view of the keyhole.
In the area, don't miss Horsetooth Falls, Horsetooth Rock and Coyote Ridge Open Space. Need more ideas? Check out this list of 200+ hikes. Don't miss any of my trip reports, sign up for an email alert at the top of this page and follow me on Facebook.
Note: There are very few trees here, so it will be warm in the summer. Please check the park's website before you go for closures due to mud, nesting birds and other issues.
Directions: From I-25, take the U.S. 34/Loveland exit. Drive west 8.3 miles and turn right on Hidden Valley Drive (there should be a small, brown sign here for Devil's Backbone Open Space). drive Hidden Valley Drive 0.2 miles to the open space park entrance.