USFS National Forest System Trails · Custer Gallatin National Forest · Montana · Updated June 2026
31504 (USFS trail 31504) is a 0.6 mi trail in Custer Gallatin National Forest, Montana. Mountain bikes are designated as allowed, Jan–Oct, December, with Class 1 e-bikes also designated.
Can I bike 31504?
| Use | Status | Season on record |
|---|---|---|
| Mountain bike | Allowed | Jan–Oct, December |
| Class 1 e-bike (pedal-assist, 20 mph) | Allowed | Jan–Oct, December |
| Class 2 e-bike (throttle, 20 mph) | Allowed | Jan–Oct, December |
| Class 3 e-bike (pedal-assist, 28 mph) | Allowed | Jan–Oct, December |
Zooming out: across Custer Gallatin National Forest, 98% of rideable trail miles are open to mountain bikes — a Bike Access Grade of A.
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About this trail
In Custer Gallatin National Forest, Montana, 31504 (USFS trail 31504) covers 0.6 mi of National Forest System trail. Everything below comes straight from the US Forest Service National Forest System Trails dataset — length, surface, slope-derived difficulty, and the specific bike and e-bike designations on record — so you can check legality before you load up. Underfoot, the trail is recorded as native material. USFS slope data puts it in the Easy band (grade band +0-5%), meaning a gentle climb — keep in mind this measures steepness, not trail technicality. Bike use is designated as allowed, typically Jan–Oct, December. The record additionally permits Class 1, Class 2, Class 3 e-bike use, Jan–Oct, December; 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 2 on the agency's 1-to-5 development scale, where 1 is the most primitive, minimally maintained tread and 5 is the most developed. Because conditions, closures, and local orders change between data refreshes, confirm the current status with the managing ranger district before you ride.
Frequently asked questions
- Can you mountain bike on 31504?
- Yes. Mountain bikes are designated as allowed on 31504 in Custer Gallatin National Forest, typically Jan–Oct, December, per USFS data.
- Are e-bikes allowed on 31504?
- Class 1, Class 2, Class 3 e-bikes are designated on 31504 in the USFS data.
- How long is 31504?
- 31504 measures about 0.6 mi in total, summed across its mapped National Forest System segments.
- What is the surface of 31504?
- USFS data records the tread surface of 31504 as native material.
- How difficult is 31504?
- Its grade-based difficulty is Easy (grade band +0-5%), 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 Custer Gallatin National Forest (USFS trail geometry isn't mapped).
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