USFS National Forest System Trails · Helena-Lewis and Clark National Forest · Montana · Updated June 2026
Thorsen Pond (USFS trail J15975) is a 1.6 mi trail in Helena-Lewis and Clark National Forest, Montana. Mountain bikes are designated as allowed year-round, with Class 1 e-bikes also designated.
Can I bike Thorsen Pond?
| 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 Helena-Lewis and Clark National Forest, 91% of rideable trail miles are open to mountain bikes — a Bike Access Grade of A.
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About this trail
In Helena-Lewis and Clark National Forest, Montana, Thorsen Pond (USFS trail J15975) covers 1.6 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. No grade band is recorded, so a steepness-based difficulty isn't available for this trail. 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. For day-of certainty on closures or seasonal orders, check directly with the ranger district, since this reflects the USFS data as of the latest refresh.
Frequently asked questions
- Can you mountain bike on Thorsen Pond?
- Yes. Mountain bikes are designated as allowed on Thorsen Pond in Helena-Lewis and Clark National Forest, year-round, per USFS data.
- Are e-bikes allowed on Thorsen Pond?
- Class 1, Class 2, Class 3 e-bikes are designated on Thorsen Pond in the USFS data.
- How long is Thorsen Pond?
- Thorsen Pond measures about 1.6 mi in total, summed across its mapped National Forest System segments.
- What is the surface of Thorsen Pond?
- USFS data records the tread surface of Thorsen Pond 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 Helena-Lewis and Clark National Forest (USFS trail geometry isn't mapped).
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