Park County, Colorado
Pike National Forest
South Park Ranger District
View this on the Colorado Trailheads Map
County Road: 12
Trail Type: Straight Through
Nearby Towns: Breckenridge, Leadville
Nearby Trails: Wheeler Lake, Halfmoon Creek, Weston Pass, Mount Bross, Birdseye Gulch, Mount Zion, Hagerman Pass, Buckskin Joe, South London Mine
Trail Length: 15.1 miles
Elevation: 10,328 to 13,198 feet
Recommended by Bill S.
Recommended by David
This is one of those trails that is popular with all offroad enthusiasts because it offers a little bit of everything. It's a great way to connect highway 9 and highway 91 from Alma to Leadville. The scenery is fantastic, including a huge mine in fairly good condition, and this is the highest continuous road in Colorado that goes over a pass.
It used to be a stagecoach road that saw heavy use, and though it was a fairly easy trail in the past it has gotten quite a bit more challenging in recent years. If you start in Alma, the dirt road is easy as you pass through the small town of Park City. The road continues as an easy one with a few bumpy sections as you work your way to the North London Mine. There are a few rocky sections for some fun during the climb.
The mine has lots of room for parking at timberline. It is very well preserved but use caution if you are near it. This is a great spot for lunch and picture taking.
The section past the mine and toward the pass is probably the most difficult. There are rocky sections as you climb to the pass and some places are very eroded. Many rocks can be avoided with careful tire placement, but some areas must be negotiated. An SUV with low clearance may get turned away here.
Just past the first hill on the way to the pass you can find the out-and-back trail to the South London Mine, a great side trip if you're on the Mosquito Pass trail. Continue to climb, and soon you find yourself at the pass and the sign for it that has been there for many, many years. The views are outstanding, and you can look to either side and see many mountain ranges.
There are many switchbacks on the west side of the pass as you work your way down. It is bumpy but not particularly technical compared to the east side. You can look down from the switchbacks to see the top section of the Birdseye Gulch trail.
Pass the Birdseye Gulch trail and enjoy the views of Mountain Lake and Diamond Lake as you descend. Soon the trail goes right by the lakes and it ends at the easy dirt roads near the Diamond Mine. Follow these roads west to the town of Leadville.
Information last updated on September 14th, 2014.
- September 6, 2014: ran by Gary, Roger and Walt
- September 17, 2011: ran by Bill S., Hoa, Julie, Mike S., Monica, Roger and Walt
- August 11, 2007: ran by Bill S., Dave B., Don, Gary, Ladd, Mark F., Matt K., Michael, Michelle, Mike V., Mike C., Mike S., Steve B., Todd and Walt
- September 3, 2005: ran by Gary and Mark F.
- August 9, 2003: ran by Jenn, Ladd, Mike C., Monica, Paul, Perry and Rob B.
From Denver, take I-70 to highway 9 through Breckenridge. Turn right on Park Hill Road in the town of Alma. This turns into County Road 10 and takes you to the town of Park City and the Mosquito Pass trailhead. Follow signs to Mosquito Pass.
Alternatively, you can take highway 285 from Denver to Fairplay and highway 9 north. Before you get to Alma you can turn left on County Road 12. This will take you to Park City and the trailhead.
If you're taking I-70 meet at the Starbucks in Downieville at exit 234. If you want to take Highway 285, meet in Conifer at the Conoco gas station.