USFS National Forest System Trails · Custer Gallatin National Forest · Montana · Updated June 2026
40945 (USFS trail 40945) is a 4.4 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 40945?
| 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
In Custer Gallatin National Forest, Montana, 40945 (USFS trail 40945) covers 4.4 mi of National Forest System trail. 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. Underfoot, the trail is recorded as native material. Based on slope, this is a Intermediate trail (grade band +8-10%); that reflects moderate gradient and is not the same as a technical MTB difficulty rating. Bike use is designated as allowed year-round. On the electric side, Class 1, Class 2, Class 3 e-bikes are also designated — Class 1 being pedal-assist only, Classes 2 and 3 adding a throttle and higher assisted 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 40945?
- Yes. Mountain bikes are designated as allowed on 40945 in Custer Gallatin National Forest, year-round, per USFS data.
- Are e-bikes allowed on 40945?
- Class 1, Class 2, Class 3 e-bikes are designated on 40945 in the USFS data.
- How long is 40945?
- 40945 measures about 4.4 mi in total, summed across its mapped National Forest System segments.
- What is the surface of 40945?
- USFS data records the tread surface of 40945 as native material.
- How difficult is 40945?
- 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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