USFS National Forest System Trails · Helena-Lewis and Clark National Forest · Montana · Updated June 2026
Slate Lake (USFS trail 1871-T) is a 4 mi trail in Helena-Lewis and Clark National Forest, Montana. Mountain-bike use here is accepted but discouraged in USFS data, with Class 1 e-bikes also designated.
Can I bike Slate Lake?
| Use | Status | Season on record |
|---|---|---|
| Mountain bike | Accepted but discouraged | — |
| Class 1 e-bike (pedal-assist, 20 mph) | Allowed | May–Aug |
| Class 2 e-bike (throttle, 20 mph) | Allowed | May–Aug |
| Class 3 e-bike (pedal-assist, 28 mph) | Allowed | May–Aug |
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
Slate Lake (USFS trail 1871-T) runs 4 mi through Helena-Lewis and Clark National Forest in Montana. The figures here are pulled from the official US Forest Service trail data for Helena-Lewis and Clark National Forest, covering the trail's mileage, tread, grade band, and the bike and e-bike uses the agency lists as designated. The tread is mapped as native material. No grade band is recorded, so a steepness-based difficulty isn't available for this trail. For traditional mountain bikes, use is discouraged according to USFS data. The record additionally permits Class 1, Class 2, Class 3 e-bike use, May–Aug; 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 3 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 Helena-Lewis and Clark National Forest.
Frequently asked questions
- Can you mountain bike on Slate Lake?
- Mountain-bike use on Slate Lake is discouraged in USFS records, though Class 1 e-bike use is designated. Confirm current rules with the managing ranger district.
- Are e-bikes allowed on Slate Lake?
- Class 1, Class 2, Class 3 e-bikes are designated on Slate Lake in the USFS data.
- How long is Slate Lake?
- Slate Lake measures about 4 mi in total, summed across its mapped National Forest System segments.
- What is the surface of Slate Lake?
- USFS data records the tread surface of Slate Lake 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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