Gross Reservoir

Total Miles
2.5

Technical Rating

2

Easy

Best Time

Summer, Fall

Trail Type

Full-Width Road

Accessible By

Show in App
Gross Reservoir
5

Trail Overview

This is a super fun, single lane road to amazing camping. You'll camp above the reservoir and fish, canoe, kayak and relax. No swimming. Open to licensed and unlicensed vehicles. Trail is open from May 15 to November 30.

Photos of Gross Reservoir

Gross Reservoir
Gross Reservoir

Difficulty

Easy. Route has small ledges and one steep, chewed-up hill (likely caused by two-wheel-drive vehicles spinning tires during climbs). Fourwheel drive and higher ground clearance is recommended. Road is very narrow in spots and backing may be necessary to get around oncoming vehicles.

History

Reservoir Expansion: At the time of this writing, a project was underway to raise the dam 131 ft., which would nearly triple capacity of reservoir. Our map shows the approximate location of the new shoreline. The road ends at a new parking lot at Waypoint 03. Access to campsites around the parking area is by hiking and horseback only.

Technical Rating

2

Status Reports

Rob Bray
Oct 13, 2025
2023 Ford Bronco
Open
Normal
Rough/Deteriorated
The trail is mostly easy, but there is one section about half way up that is super washed out with ruts. Might be difficult without larger tires and/or locking differential. Most 4x4 could probably manage with precision and momentum.
Ryan W.
Aug 16, 2025
4x4
Open
Normal
Dusty
Muddy/Wet
Winiger Ridge can be a confusing area the first out. The Forsythe Trail Head can lead you down a couple of different paths. Check the map at the restrooms and you’ll see the path that leads to all the campsites, that’s the easy down-and-back trail. Forsythe Canyon Trail and 68 are different paths. The main trail is a simple dirt trail that is one lane with multiple pull-offs. There’s one semi-steep part that stock height 2WDs can make with little technical effort. There are over 20 campsites that are first come first serve, but there’s also camping available at the trail end. It was overcast and a little rainy, but a lot of fun for simple getaway!
Mike Walsh
Aug 05, 2025
2019 Toyota 4Runner
Permanently Closed
Posted Private Property
Locked Gate
Coordinates take you to a gate marked private property. I kept driving to another turn off up the road to Gross Res campground and to the Res parking lot. Can get rocky, one section of rutted sand moguls. Damn construction not the most scenic.
Gerardo Ochoa
Jul 24, 2025
Open
Muddy/Wet

Gross Reservoir can be accessed by the following ride types:

  • High-Clearance 4x4
  • SUV
  • SxS (60")
  • ATV (50")
  • Dirt Bike

Access Description

From Nederland: Head south from roundabout 2 miles and turn left on Magnolia Drive, C.R.132. Go 5.4 miles east and turn right on C.R. 68. Go another 2.0 miles to fenced parking area on right. From Boulder: Take Canyon Highway 119 about 4 miles west to Magnolia Drive on left. Go another 6.6 miles to C.R. 68 on left. Parking lot at start of trail is on right in another 2.1 miles.

Gross Reservoir Map

Popular Trails

East Bolam Pass

East Bolam Pass

Total Miles
9.2
Tech Rating
4 Moderate
Best Time
Su / Fa
BLM Route 196

BLM Route 196

Total Miles
3.3
Tech Rating
2 Easy
Best Time
Fa / Sp
6102C

6102C

Total Miles
1.0
Tech Rating
4 Moderate
Best Time
Sp / Su / Fa / Wi
Dud Bob's

Dud Bob's

Total Miles
6.3
Tech Rating
6 Moderate
Best Time
Sp / Su / Fa

The onX Offroad Difference

onX Offroad combines trail photos, descriptions, difficulty ratings, width restrictions, seasonality, and more in a user-friendly interface. Available on all devices, with offline access and full compatibility with CarPlay and Android Auto. Discover what you’re missing today!