It’s not every day that a five-mile downhill flow trail with over 1,400 feet of vert and filled with purpose-built jumps and drops is built in Northern California, but that’s exactly what riders will find on Colby Mountain outside of Chico. And it’s just the beginning of an epic new 36-mile trail system.
Introducing the Humboldt Drop
Technically, the Humboldt Drop measures in at 4.9 miles of downhill ripping, just shy of a full five. There’s almost no vertical gain along its length, and it drops 1,434 vertical feet off a road near the top of Humboldt Peak. And this trail introduces an entirely new type of riding to Chico mountain bikers.
Chico is known for its extremely rocky singletrack, but the new Humboldt Drop trail defies this stereotype with purpose-built, flow-style mountain biking crafted by renowned trail builders Rock Solid Trail Contracting. “There’s almost no rocks in sight, except for the rock gardens that they [made],” said Whitney Garcia, Co-manager of local bike advocacy and maintenance organization, Chico Velo.
“We’re talking tabletops, big jumps, multiple drops,” Garcia continued, saying, “everything can be ridden around or avoided.” This allows everybody from beginners (if they’re willing to walk some of the drops) to experts to ride the trail. However, given the scale of the tabletops and drops, Humboldt Drop is clearly not intended for beginner riders and is rated black diamond on the latest trail maps.
For most riders, one lap isn’t enough. To head back up for seconds, you can either choose to pedal up the nearby forest service road or shuttle to the top with some buddies.
This new purpose-built downhill trail is already transforming how people view Chico’s riding scene. Local riders are undeniably stoked, and out-of-town mountain bikers are already driving for hours from the Bay Area, Southern Oregon, and beyond to sample the new goods in Chico.
While the Humboldt Drop is the newest trail making waves in Chico, it’s just the beginning of a 36-mile trail system on Colby Mountain that’s currently in the works.
36 miles of new MTB trails coming to Colby Mountain
The Colby Mountain Trail System, of which the Humboldt Drop is just one part, is being built in the Lassen National Forest about an hour up into the mountains from downtown Chico. While Chico is home to some 109,000 residents, they were in dire need of more trails to spread people out and provide recreational opportunities. Colby Mountain was a great candidate for trail development, as the area’s sparse trails and existing Forest Service roads have long been popular for recreation.
Thad Walker, District Manager/ Conservation Project Coordinator for the Butte County Resource Conservation District (BCRCD), saw the need for more trail-based recreation and broached the topic with the US Forest Service. The USFS responded that they already couldn’t maintain the few existing trails in the Lassen National Forest and that they needed to focus on forest health, not just recreation.
Chico Velo took the cue from the USFS and has since taken the lead on trail maintenance across Butte County with their Trailworks program. They’re now in charge of trail maintenance in Chico’s main trail system in Bidwell Park and will be the maintenance partner going forward for the new Colby Mountain Trail System. As for forest health, BCRCD (essentially a local government agency) brought their resources to bear to address the USFS’s concerns.
Broad swathes of Northern California have been decimated by wildfires in recent years, yet Colby Mountain has somehow come through unscathed. The area is still “pristine forest,” according to Garcia, and of particular ecological importance in the region.
So, BCRCD “wrote a grant within that area of the Lassen National Forest kind of surrounding Colby on 20,000 acres to do a large watershed landscape-level forest health project,” according to Walker. They were able to include the trail proposals on Colby Mountain, “and that’s how we were kind of able to also progress the recreation, because we were bringing that forest health element into it.”
The trails weren’t simply shoehorned into the proposal. The trail development also benefits the national forest by reducing unauthorized trail building and the use of non-system trails, and by allowing the USFS to more easily maintain firebreaks established during previous wildfires.
While Humboldt Drop is bike-optimized, most of the trails are designed to be multi-use. They’re even building a one-mile forest health education trail so they can “bring middle schoolers up studying natural science, to learn about their watershed,” according to Walker. The trailhead will also host educational exhibits documenting the area’s tribal history.
More new trails are ready to ride on Colby Mountain
In addition to the Humboldt Drop, a 9-mile cross country trail was also completed in 2025. Known as the “Escape Trail,” this MTB-accessible two-way trail offers ~1000 feet of climbing and descending along its length.
The Escape Trail “starts at the Colby Mountain Lookout and kind of follows this ridge down and actually kind of loops back onto itself,” said Garcia. “There are lots of avoidable features: there’s little jumps, a few berms, but mostly it’s very pedally, just to engage a rider and just take them through the forest.”
In total, about 16 miles of the 36-mile vision have been built, largely thanks to $1 million in grant funding secured through the American Rescue Plan Act.
More trails planned, and projected completion date
The next 20 miles of trails will include more mountain bike-optimized downhill trails. “Then we’ll also have some more adventure trails,” said Walker. Envision “a longer, narrow trail that goes way out on a high ridge that gets you 360° views from the valley all the way over to Mount Lassen.” This adventure-style trail will have a hand-built singletrack feel to it, versus the machine-built flow on Humboldt Drop. Many of the planned trails will also be multi-use and open to hikers and equestrians.
The final completion date for the remaining trails is ultimately dependent on funding. Garcia said, “We have a strong indication that we’re going to get the funding” for the future trails. She noted that the rest of the build is estimated to cost $3 million.
For his part, Walker hesitated to give a date, saying that “[when] you start putting a lot of trail in the ground, you have to be able to maintain it. I think for the short term, we’re really focused on kind of what we have on the ground.”
While we can’t say definitively when construction will begin on the next phase, the brand-new Humboldt Drop and Escape trails are already providing flowy new downhill and cross-country trail experiences that are radically transforming the mountain bike scene near Chico. And with more trails on the horizon, it will only get better from here.
Know about a new trail project we should cover? Whether you’re breaking ground on the next must-ride destination or putting the finishing touches on a neighborhood flow trail, we want to hear about it. Drop us a line at [email protected] with high-quality photos of your build, plus details like trail mileage, location, difficulty, and what makes it special. We’re always on the hunt for the next great trail story, and there’s a good chance your project could be featured in an upcoming article.
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