USFS National Forest System Trails · Grand Mesa, Uncompahgre and Gunnison National Forests · Colorado · Updated June 2026
Fourty Seven (USFS trail 6100) is a 4.6 mi trail in Grand Mesa, Uncompahgre and Gunnison National Forests, Colorado. Mountain bikes are designated as allowed year-round, with Class 1 e-bikes also designated.
Can I bike Fourty Seven?
| Use | Status | Season on record |
|---|---|---|
| Mountain bike | Allowed | year-round |
| Class 1 e-bike (pedal-assist, 20 mph) | Allowed | year-round |
| Class 2 e-bike (throttle, 20 mph) | Allowed | year-round |
| Class 3 e-bike (pedal-assist, 28 mph) | Allowed | year-round |
Zooming out: across Grand Mesa, Uncompahgre and Gunnison National Forests, 96% of rideable trail miles are open to mountain bikes — a Bike Access Grade of A.
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About this trail
Fourty Seven (USFS trail 6100) is a 4.6 mi trail in Grand Mesa, Uncompahgre and Gunnison National Forests, Colorado. This profile summarizes what the official US Forest Service trail record says about riding it: how long the trail is, what it's built on, how steep the route grades out, and which forms of bike use the agency has designated. USFS records list its surface as native material. Based on slope, this is a Advanced trail (grade band 12-20%); that reflects steep gradient and is not the same as a technical MTB difficulty rating. Bike use is designated as allowed year-round. The record additionally permits Class 1, Class 2, Class 3 e-bike use; recall that Class 1 is pedal-assist, while Class 2 adds a throttle and Class 3 a higher cutoff speed. The route is mapped as USFS Trail Class 3 on the agency's 1-to-5 development scale, where 1 is the most primitive, minimally maintained tread and 5 is the most developed. Treat this as a planning reference rather than a live conditions report, and verify any time-sensitive closure or order with the ranger district that manages Grand Mesa, Uncompahgre and Gunnison National Forests.
Frequently asked questions
- Can you mountain bike on Fourty Seven?
- Yes. Mountain bikes are designated as allowed on Fourty Seven in Grand Mesa, Uncompahgre and Gunnison National Forests, year-round, per USFS data.
- Are e-bikes allowed on Fourty Seven?
- Class 1, Class 2, Class 3 e-bikes are designated on Fourty Seven in the USFS data.
- How long is Fourty Seven?
- Fourty Seven measures about 4.6 mi in total, summed across its mapped National Forest System segments.
- What is the surface of Fourty Seven?
- USFS data records the tread surface of Fourty Seven as native material.
- How difficult is Fourty Seven?
- Its grade-based difficulty is Advanced (grade band 12-20%), derived from USFS slope data. This reflects steepness, not technical mountain-bike difficulty.
How we read this data
Grade-based difficulty above is the USFS grade (route steepness), not a technical mountain-bike rating — a gentle-grade trail can still be rocky or technical, and vice versa. Bike and e-bike status come verbatim from the USFS managed-use fields for this trail; we never infer access we can't cite. See our methodology for how the dataset is built and what each field means.
Where it is
Approximate location of Grand Mesa, Uncompahgre and Gunnison National Forests (USFS trail geometry isn't mapped).
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