USFS National Forest System Trails · Pike and San Isabel National Forests · Colorado · Updated June 2026
Twelvemile Lake (USFS trail 173) is a 1.5 mi trail in Pike and San Isabel National Forests, Colorado. Mountain-bike use here is accepted but discouraged in USFS data, with Class 1 e-bikes also designated.
Can I bike Twelvemile Lake?
| Use | Status | Season on record |
|---|---|---|
| Mountain bike | Accepted but discouraged | — |
| Class 1 e-bike (pedal-assist, 20 mph) | Allowed | Jun–Dec |
| Class 2 e-bike (throttle, 20 mph) | Allowed | Jun–Dec |
| Class 3 e-bike (pedal-assist, 28 mph) | Allowed | Jun–Dec |
Zooming out: across Pike and San Isabel National Forests, 51% of rideable trail miles are open to mountain bikes — a Bike Access Grade of B.
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About this trail
Twelvemile Lake (USFS trail 173) runs 1.5 mi through Pike and San Isabel National Forests in Colorado. 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. 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. On the electric side, Class 1, Class 2, Class 3 e-bikes are also designated (Jun–Dec) — Class 1 being pedal-assist only, Classes 2 and 3 adding a throttle and higher assisted speed. Its USFS Trail Class (the agency's 1-to-5 development rating) isn't recorded for this segment. 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 Twelvemile Lake?
- Mountain-bike use on Twelvemile 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 Twelvemile Lake?
- Class 1, Class 2, Class 3 e-bikes are designated on Twelvemile Lake in the USFS data.
- How long is Twelvemile Lake?
- Twelvemile Lake measures about 1.5 mi in total, summed across its mapped National Forest System segments.
- What is the surface of Twelvemile Lake?
- USFS data records the tread surface of Twelvemile 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 Pike and San Isabel National Forests (USFS trail geometry isn't mapped).
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