USFS National Forest System Trails · Boise National Forest · Idaho · Updated June 2026
Willow Spur (USFS trail 204004) is a 0.9 mi trail in Boise National Forest, Idaho. Mountain bikes are designated as allowed, Jun–Sep, with Class 1 e-bikes also designated.
Can I bike Willow Spur?
| Use | Status | Season on record |
|---|---|---|
| Mountain bike | Allowed | Jun–Sep |
| Class 1 e-bike (pedal-assist, 20 mph) | Allowed | Jun–Sep |
| Class 2 e-bike (throttle, 20 mph) | Allowed | Jun–Sep |
| Class 3 e-bike (pedal-assist, 28 mph) | Allowed | Jun–Sep |
Zooming out: across Boise National Forest, 99% of rideable trail miles are open to mountain bikes — a Bike Access Grade of A.
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About this trail
Willow Spur (USFS trail 204004) is a 0.9 mi trail in Boise National Forest, Idaho. 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. Underfoot, the trail is recorded 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, typically Jun–Sep. On the electric side, Class 1, Class 2, Class 3 e-bikes are also designated (Jun–Sep) — 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 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. 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 Willow Spur?
- Yes. Mountain bikes are designated as allowed on Willow Spur in Boise National Forest, typically Jun–Sep, per USFS data.
- Are e-bikes allowed on Willow Spur?
- Class 1, Class 2, Class 3 e-bikes are designated on Willow Spur in the USFS data.
- How long is Willow Spur?
- Willow Spur measures about 0.9 mi in total, summed across its mapped National Forest System segments.
- What is the surface of Willow Spur?
- USFS data records the tread surface of Willow Spur 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 Boise National Forest (USFS trail geometry isn't mapped).
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