USFS National Forest System Trails · Custer Gallatin National Forest · Montana · Updated June 2026
Stag Rock (USFS trail 4421) is a 5.1 mi trail in Custer Gallatin National Forest, Montana. Mountain bikes are designated as allowed year-round, with Class 1 e-bikes also designated.
Can I bike Stag Rock?
| 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 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
Stag Rock (USFS trail 4421) is a 5.1 mi trail in Custer Gallatin National Forest, Montana. 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 Intermediate band (grade band +8-10%), meaning a moderate climb — keep in mind this measures steepness, not trail technicality. Mountain bikes are allowed, open year-round in the data. 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 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. 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 Custer Gallatin National Forest.
Frequently asked questions
- Can you mountain bike on Stag Rock?
- Yes. Mountain bikes are designated as allowed on Stag Rock in Custer Gallatin National Forest, year-round, per USFS data.
- Are e-bikes allowed on Stag Rock?
- Class 1, Class 2, Class 3 e-bikes are designated on Stag Rock in the USFS data.
- How long is Stag Rock?
- Stag Rock measures about 5.1 mi in total, summed across its mapped National Forest System segments.
- What is the surface of Stag Rock?
- USFS data records the tread surface of Stag Rock as native material.
- How difficult is Stag Rock?
- Its grade-based difficulty is Intermediate (grade band +8-10%), 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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