USFS National Forest System Trails · Custer Gallatin National Forest · Montana · Updated June 2026
Lower Lake Fork (USFS trail 2.1) is a 1.7 mi trail in Custer Gallatin National Forest, Montana. Mountain bikes are designated as allowed year-round, with no Class 1 e-bike designation on record.
Can I bike Lower Lake Fork?
| Use | Status | Season on record |
|---|---|---|
| Mountain bike | Allowed | year-round |
| Class 1 e-bike (pedal-assist, 20 mph) | Restricted | — |
| Class 2 e-bike (throttle, 20 mph) | Restricted | — |
| Class 3 e-bike (pedal-assist, 28 mph) | Restricted | — |
Zooming out: across Custer Gallatin National Forest, 98% of rideable trail miles are open to mountain bikes — a Bike Access Grade of A.
Watch Custer Gallatin National Forest for access changes
Email me when USFS mountain-bike or e-bike designations change for trails in Custer Gallatin National Forest. Free, unsubscribe anytime.
About this trail
Lower Lake Fork (USFS trail 2.1) is a 1.7 mi trail in Custer Gallatin National Forest, Montana. 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. Based on slope, this is a Easy trail (grade band +0-5%); that reflects gentle gradient and is not the same as a technical MTB difficulty rating. Bike use is designated as allowed year-round. No e-bike class (1, 2 or 3) is designated on this trail in the USFS data, so treat it as a non-motorized route unless a posted order says otherwise. 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 Custer Gallatin National Forest.
Frequently asked questions
- Can you mountain bike on Lower Lake Fork?
- Yes. Mountain bikes are designated as allowed on Lower Lake Fork in Custer Gallatin National Forest, year-round, per USFS data.
- Are e-bikes allowed on Lower Lake Fork?
- No e-bike class (1, 2 or 3) is designated on Lower Lake Fork in the USFS data.
- How long is Lower Lake Fork?
- Lower Lake Fork measures about 1.7 mi in total, summed across its mapped National Forest System segments.
- What is the surface of Lower Lake Fork?
- USFS data records the tread surface of Lower Lake Fork as native material.
- How difficult is Lower Lake Fork?
- Its grade-based difficulty is Easy (grade band +0-5%), 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 Custer Gallatin National Forest (USFS trail geometry isn't mapped).
Where to stay near Custer Gallatin National Forest
Find hotels, cabins, and vacation rentals near Custer Gallatin National Forest — plan your ride.
Top-rated places to stay near Custer Gallatin National Forest
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Riding Custer Gallatin National Forest?
Trail-access updates and trip ideas by email.