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Backcountry Mountain Biking near Big Sky, Montana

Head deep into the mountains in Southwestern Montana with this backcountry guidebook.

Mountain Biking Moderate, Difficult, Severe

Portal to Porcupine Shuttle
Photo: Greg Heil


The Southern Gallatins near Big Sky provide a stunningly-beautiful landscape that is quintessential Montana: wide, shallow rivers; endless meadows; rolling ridges covered in towering pines; and vaulted peaks off in the distance standing sentry above the more moderate landscape below. By "more moderate" and "rolling ridges," I mean mountain ridges that require 4,000-5,000 vertical feet of climbing to ascend, oftentimes with substantial hike-a-bike involved. From a distance, the mountains look soft, but up close, the sheer scale of the undertaking weighs down on you, and you realize you're in for a big day in the mountains no matter what.

The backcountry riding near Big Sky isn't nearly as well developed or maintained as the in-bounds riding closer to the resort or even the backcountry trails closer to Bozeman. Many of these trails are out there. To simply reach the trailhead requires most local riders to drive an hour to an hour and a half from the nearby population centers, and only then do you get on your bike and start pedaling deep into the mountains. The difficult access combined with the difficult riding makes for little-ridden singletrack that provides a fantastic wilderness mountain bike experience... as long as you can follow the trails.

In my experience, I found most of the non-motorized backcountry singletrack to be very faint, grassy, and almost non-existent in places. As a result, the best trails I rode in the backcountry were all moto trails, with the dirt bike traffic helping to keep the trails open, cleared of trees, and navigable. That said, even some of the moto trails could have used some chainsaw work, as the motos had torn deep ruts while bypassing around many of the downed trees.

The best bets for easy-to-follow singletrack are definitely the rides closest to Big Sky. The Mules loop is a big-mountain classic, but since you can ride it from downtown, it sees a bit more traffic. The Grizzly Loop area is also easily-accessible, and the trails there are actually quite beginner-friendly. It's also easy to follow these trails, although the many tracks created by heavy horse traffic can make navigation difficult.

Portal to Porcupine is a true backcountry gem that's well worth the effort, but depending on the year, it could need some maintenance. But for the adventurous enduro rider looking for a rewarding descent, it's a must-ride!

Finally, I do need to note that many sources and locals that I consulted mentioned Taylor Fork as a top backcountry riding zone. Located south of Big Sky, the area looks very promising... yet I wasn't able to put together a ride of high enough quality in this area to include it in this guidebook. If you're a local and want to share the goods to get much-needed tire traffic on these backcountry trails, please feel free to publish your route(s) in this area by using our Adventure Studio tool, then slide into my DMs and let me know. I'll be sure to add your expertise to this guidebook.


The Big Sky area is renowned as prime grizzly bear country. Signs at every trailhead warn that bears are highly active in the area. Mountain biking is considered a high-risk activity in grizzly bear country due to the quiet speed of a bicycle and how quickly you can accidentally sneak up on a bear when rounding a blind turn. To mitigate this risk, make plenty of noise while riding, try to ride with a group of people, and consider attaching a bear bell to your handlebars. Also, make certain that you carry bear spray with you every time you ride, in case you do get into an encounter with a grizzly.

Routes included

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