USFS National Forest System Trails · Custer Gallatin National Forest · Montana · Updated June 2026
South Fork Flathead Creek (USFS trail 542) is a 6 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 South Fork Flathead Creek?
| Use | Status | Season on record |
|---|---|---|
| Mountain bike | Allowed | year-round |
| Class 1 e-bike (pedal-assist, 20 mph) | Allowed | Jun–Dec |
| Class 2 e-bike (throttle, 20 mph) | Allowed | Jun–Dec |
| Class 3 e-bike (pedal-assist, 28 mph) | Allowed | Jun–Dec |
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
South Fork Flathead Creek (USFS trail 542) runs 6 mi through Custer Gallatin National Forest in 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. USFS records list its surface as native material. No grade band is recorded, so a steepness-based difficulty isn't available for this trail. Bike use is designated as allowed year-round. The record additionally permits Class 1, Class 2, Class 3 e-bike use, Jun–Dec; 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 4 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 South Fork Flathead Creek?
- Yes. Mountain bikes are designated as allowed on South Fork Flathead Creek in Custer Gallatin National Forest, year-round, per USFS data.
- Are e-bikes allowed on South Fork Flathead Creek?
- Class 1, Class 2, Class 3 e-bikes are designated on South Fork Flathead Creek in the USFS data.
- How long is South Fork Flathead Creek?
- South Fork Flathead Creek measures about 6 mi in total, summed across its mapped National Forest System segments.
- What is the surface of South Fork Flathead Creek?
- USFS data records the tread surface of South Fork Flathead Creek as native material.
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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