Boulder, ColoradoOwned and Operated by Denver Water
Recreation Manager – Denver Water - eastside manager
Roosevelt National Forest – Boulder District - west side manager
Gross Reservoir is open to
non-motorized car-top boats on Memorial Day.
This is a fantastic high mountain lake. Gross Reservoir is free
to the public, has fishing, hiking, picnicking, camping and paddling.
We suggest you try a touring boat or two and tour this lake.
There are fingers of the lake to explore and to disappear into.
Take Hwy 93 north from Golden to Hwy 72. Turn left (west) on Hwy
72 toward Pinecliffe to County Road 85. Follow County Road 85, which
turns into western Gross Dam Road. It will take you to both the
north and south access points. To reach the dam from Boulder, take
Flagstaff Road west until it turns into eastern Gross Dam Road.
You can see our map online
on how to get to Gross Res. or our topo
Open year round
Operating Hours: one half hour before sunrise to half an hour after
West side USFS closure Late Fall Early Spring Check with the USFS Boulder
District for closure dates.
Cold water fishing; stocked by Colorado Division of Wildlife. Ice fishing is allowed at your own risk in the winter.
The east side developed areas are for day use only. Sheltered tables
Access to the reservoir from North Point picnic area, South Shore
Recreation Area trailhead to South Boulder Creek Inlet.
Limited access. High clearance vehicles required. West side managed
by Roosevelt National Forest. Area has seasonal closure; check with
Boulder District. Usually open for Memorial Day through until the first snowfall in the fall. There is not a fee or reservation for camping on the west side of the lake, access by a rough dirt road on the west side. Maps may show access from the East Side on Lake Shore Drive, but this access is blocked. The turn off of Magnolia is CO Hwy 68 to FS Road 359. You can use Google Maps to see the camping area.
No contact with water. Swimming, wading, scuba diving or other water activities are not allowed on the reservoir. You must stay on top of the water like kayaking, canoeing, in the winter ski touring or ice skating. On ice activities are legal and at your own risk. Strong winds blow across the reservoir, so on ice activites are not ideal.
Denver Water – 303-628-6000 (owns the water)
Colorado Division of Wildlife – 303-291-7227 (for fishing info)
USFS Boulder District – 303-541-2500 (West side of the lake, including camping)
Boulder Sheriff – 303-441-3624
A note from the Denver Water Board
For those who worked on the FERC Recreation Management Plan for
Gross and were anticipating the opening of the 2003 boating season,
we apologize that we have had to delay the opening. We have received
approval of the Recreation Management Plan from FERC and are working
toward opening the reservoir for non-motorized car-top boats for
the 2005 season. We will continue to update this web page as progress
is made. For more information on our plans for Gross Reservoir,
visit the management plan pages.
Named for Denver Water former Chief Engineer Dwight D. Gross, the
reservoir was completed in 1954. It serves as a combination storage
and regulating facility for water that flows under the Continental
Divide through the Moffat Tunnel. Standing 340 feet above the South
Boulder Creek streambed, Gross Dam contains some 627,559 cubic yards
of concrete. Gross Reservoir has a surface area of 440 acres and
10.9 miles of shoreline.