USFS National Forest System Trails · Black Hills National Forest · South Dakota · Updated June 2026
Nemo 251 (USFS trail 8251) is a 2.1 mi trail in Black Hills National Forest, South Dakota. Mountain-bike use here is accepted but discouraged in USFS data, with Class 1 e-bikes also designated.
Can I bike Nemo 251?
| Use | Status | Season on record |
|---|---|---|
| Mountain bike | Accepted but discouraged | — |
| 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 Black Hills National Forest, 34% of rideable trail miles are open to mountain bikes — a Bike Access Grade of C.
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About this trail
In Black Hills National Forest, South Dakota, Nemo 251 (USFS trail 8251) covers 2.1 mi of National Forest System trail. The figures here are pulled from the official US Forest Service trail data for Black Hills National Forest, covering the trail's mileage, tread, grade band, and the bike and e-bike uses the agency lists as 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. For traditional mountain bikes, use is discouraged according to USFS 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 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 Black Hills National Forest.
Frequently asked questions
- Can you mountain bike on Nemo 251?
- Mountain-bike use on Nemo 251 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 Nemo 251?
- Class 1, Class 2, Class 3 e-bikes are designated on Nemo 251 in the USFS data.
- How long is Nemo 251?
- Nemo 251 measures about 2.1 mi in total, summed across its mapped National Forest System segments.
- What is the surface of Nemo 251?
- USFS data records the tread surface of Nemo 251 as native material.
- How difficult is Nemo 251?
- 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 Black Hills National Forest (USFS trail geometry isn't mapped).
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