Gross Reservoir

Looking for a quiet outdoor escape that’s still close to Boulder? Gross Reservoir is one of the area’s best-kept secrets—a scenic, high-elevation lake tucked into the foothills just 45 minutes southwest of town. With no motorboats allowed, jaw-dropping mountain views, and plenty of space to roam, Gross Reservoir is a haven for anyone craving peace and nature.

How to Get to Gross Reservoir from Boulder

Getting there is half the fun. From downtown Boulder:

• Take Flagstaff Road west (starting near Chautauqua Park).

• Continue for about 13 miles as the road winds through pine forests and offers panoramic views.

• Turn left on Gross Dam Road and follow the signs—note that the last mile is a well-maintained dirt road.

Once there, you’ll find access points for kayaking, hiking, fishing, and enjoying stunning vistas. The North Shore is popular with paddleboarders and canoeists, while the South Side is known for epic overlooks and more rugged trails.

Why Boulder Locals Love Gross Reservoir

• Quiet waters: Gas-powered boats are prohibited, making it perfect for paddleboarding and kayaking.

• Fishing friendly: Try your luck with lake trout, brown trout, or kokanee salmon.

• Scenic hiking: Trails wrap around rocky cliffs and shady forest ridges.

• Wildlife sightings: Bald eagles, osprey, mule deer, and even the occasional moose roam the area.

The vibe here is wild and remote, even though it’s surprisingly close to town. With the Flatirons in the distance and cool mountain air brushing the pines, it’s the kind of place you’ll want to revisit again and again.

Gross Reservoir, Boulder County – Elevation 7,225 ft.
A stunning high-altitude escape surrounded by forested cliffs, just southwest of Boulder, Colorado.

Fast Facts About Gross Reservoir

• Elevation: 7,225 feet above sea level

• Built: In 1954 by Denver Water

• Name origin: Honoring Dwight D. Gross, a former chief engineer at Denver Water

• Size: 418 surface acres

• Dam expansion: Underway to nearly triple the water storage, making it one of Colorado’s largest

Tips for Your Trip

• There’s no swimming allowed.

• Pack in your supplies—there are no food stands, restrooms, or water fountains.

• Dogs are welcome, but must stay on a leash.

• Be prepared for changing weather. It’s often 10–15°F cooler than Boulder and storms can roll in fast.

Final Thoughts

Gross Reservoir isn’t just a pretty spot—it’s a whole experience. From its reflective waters and rocky cliffs to its tranquil trails and lack of crowds, this reservoir gives you everything you love about Colorado in one quiet, unforgettable setting.

For those in Boulder looking to recharge, reflect, or just float peacefully on a paddleboard, Gross Reservoir is where serenity meets elevation. Add it to your must-visit list—you’ll be glad you did.

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