Best lakes near Boulder
The best lakes near Boulder, Colorado split into two kinds: high alpine lakes up the canyons, like Brainard, Lost, and Diamond in the Indian Peaks, that you hike to for the big mountain payoff, and in-town and foothills lakes and reservoirs, like Boulder Reservoir and Gross Reservoir, where you can actually swim and paddle close to home.
Outdoor Boulder › Best lakes
Boulder's lakes come in two very different flavors, and it helps to know which one you're after. Up the canyons, in the Indian Peaks, are the alpine lakes: cold, clear, ringed by peaks, and reached on a hike (short or long). Down low, in town and out in the foothills, are the reservoirs and lakes where you can swim, paddle, or just walk a flat loop by the water without much of a drive.
We keep the descriptions honest and qualitative here (alpine or in-town, how far in, what it offers) and link each lake to its full guide, where you'll find the exact distance, elevation, permits, and access rules. Want more? The Boulder hiking hub sorts every trail on the site by difficulty, and the swimming and paddling guide covers where to actually get in the water.
The best lakes near Boulder at a glance
Every lake below links to its own guide with verified facts, parking, permits, and dog rules. Pick one and go.
| Lake | Where | Why go |
|---|---|---|
| Brainard Lake | Indian Peaks | The classic high-country basecamp. Drive to a subalpine lake ringed by peaks, then walk on to Long, Isabelle, and Mitchell lakes above it. |
| Lost Lake | Hessie / Eldora | The most family-friendly alpine lake near Boulder, reached on a shorter walk in from the Hessie Trailhead near Eldora. A real mountain lake without a huge day. |
| Diamond Lake | Indian Peaks | The wildflower payoff. A steeper climb from Hessie leads to a meadow-rimmed lake that lights up in midsummer, with waterfalls along the way. |
| Boulder Reservoir | North Boulder | The go-to for actually getting in the water: a summer swim beach, paddling, and flat shoreline walking, all a few minutes from town. |
| Gross Reservoir | Foothills, south of town | The quiet one. A mountain reservoir tucked in the foothills that's better for calm, low-key paddling and a scenic drive than for crowds. |
| Wonderland Lake | North Boulder | A flat, short loop around a small lake with big Flatirons views and plenty of birds. Easy for kids and grandparents, and close in. |
| Mud Lake | Near Nederland | Easy, forested high-country loops around a quiet lake up near Nederland. Cooler on a hot day, with gentle grades throughout. |
Alpine lakes up the canyons
These are the high mountain lakes you drive up a canyon and then hike to. They sit well above town, so they're cooler, they melt out later, and the scenery is the full Indian Peaks postcard. Access to the trailheads is the catch, so read the guide before you go.
- Brainard Lake: The classic high-country basecamp. Drive to a subalpine lake ringed by peaks, then walk on to Long, Isabelle, and Mitchell lakes above it.
- Lost Lake: The most family-friendly alpine lake near Boulder, reached on a shorter walk in from the Hessie Trailhead near Eldora. A real mountain lake without a huge day.
- Diamond Lake: The wildflower payoff. A steeper climb from Hessie leads to a meadow-rimmed lake that lights up in midsummer, with waterfalls along the way.
If you only do one, Brainard Lake is the easiest to enjoy at any effort level, because you can walk right to the lake or push on to the higher ones. For a shorter family walk to a real alpine lake, take Lost Lake from Hessie. For the midsummer wildflowers, climb to Diamond Lake.
In-town and foothills lakes and reservoirs
These are the close-in lakes: no long drive, no big climb, and in some cases you can actually get in the water. They're the easy answer for a hot afternoon, a paddle, a flat walk, or an outing with little kids.
- Boulder Reservoir: The go-to for actually getting in the water: a summer swim beach, paddling, and flat shoreline walking, all a few minutes from town.
- Gross Reservoir: The quiet one. A mountain reservoir tucked in the foothills that's better for calm, low-key paddling and a scenic drive than for crowds.
- Wonderland Lake: A flat, short loop around a small lake with big Flatirons views and plenty of birds. Easy for kids and grandparents, and close in.
- Mud Lake: Easy, forested high-country loops around a quiet lake up near Nederland. Cooler on a hot day, with gentle grades throughout.
Lakes you can swim and paddle
For actually getting in the water, Boulder Reservoir is the main event, with a summer swim beach and room to paddle close to town. Gross Reservoir up in the foothills is the quieter choice for calm paddling. The high alpine lakes are a different story: many limit or ban swimming and dogs to protect the water supply, and the water stays icy cold even at the height of summer, so treat those as look-but-don't-swim unless the lake's own guide says otherwise. See the swimming and paddling guide for the full rundown.
Lake hikes near Boulder: what to know
The alpine lakes sit high, so they hold snow and ice long after town has dried out, and afternoon thunderstorms build fast over the peaks in summer. Start early, carry more water and layers than you think you'll need, and turn around if the sky turns. Access is the other planning piece: the popular trailheads up the canyons use fees, timed-entry reservations, or a seasonal shuttle, and the lots fill early. Each lake's own guide has the current parking, permit, and access details, so check it the night before you go.
Lakes near Boulder: FAQ
What's the best alpine lake hike near Boulder?
Brainard Lake, up in the Indian Peaks, is the classic. You can drive close to the lake itself and then hike on to a string of higher lakes (Long, Isabelle, and Mitchell) below jagged peaks, so it works for both an easy stroll and a bigger day. For a shorter walk to a true mountain lake, Lost Lake from the Hessie Trailhead is the friendlier pick.
What's the easiest lake to reach near Boulder?
For a lake right in town with no real effort, Wonderland Lake in north Boulder is a flat, short loop, and the shoreline at Boulder Reservoir is level and easy. If you want an alpine lake without a long climb, Lost Lake via Hessie is the gentlest option up in the high country, though it still involves a real walk in.
Which lakes near Boulder can you swim or paddle in?
Boulder Reservoir is the main spot for swimming and paddling, with a designated summer swim beach and boat access close to town. Gross Reservoir up in the foothills is better for quiet, low-key paddling. Many high alpine lakes in the Indian Peaks limit or prohibit swimming and dogs to protect the watershed, so check the specific lake's guide and rules before you go in.
When do the high lakes near Boulder melt out?
The alpine lakes up in the Indian Peaks (Brainard, Lost, Diamond) hold snow and ice far later than town. They generally aren't reliably clear and hikeable until well into summer, and the road and upper trails can stay snowbound into early summer. Wildflowers peak in midsummer. Down low, the in-town lakes and reservoirs are open and usable much earlier in the year.
Do I need a permit or reservation for Brainard Lake or Hessie?
Access to these trailheads is the real hurdle, not the walk. The Brainard Lake area charges an entry fee and, in peak season, uses a timed-entry vehicle reservation system that fills up, so plan ahead. The Hessie Trailhead (the start for Lost Lake and Diamond Lake) has very limited parking and uses a seasonal weekend shuttle from Nederland. Each lake's guide has the current fee, reservation, and parking details.
Recommended nearby
[CLIENT SLOT: featured Boulder gear shop]
[One honest line: where to grab a paddle rental, water shoes, or layers before a lake day.]
[CLIENT SLOT: post-hike cafe]
[One honest line: a coffee or breakfast stop on the way up the canyon or back into town.]
[CLIENT SLOT: SUP or kayak rental]
[One honest line: where to rent a board or kayak for the reservoir.]
Sources and notes
This is a synthesis page. The call on each lake (alpine or in-town, easy or involved) comes from our own full guide for that place, and every specific fact (distance, elevation gain, parking, permits, and dog and swim rules) lives on the linked guide, drawn there from the City of Boulder Open Space & Mountain Parks, Boulder County Parks & Open Space, the US Forest Service (Indian Peaks Wilderness), and each site's official managing agency. Trail conditions, water levels, and seasonal rules change, so check the guide (and the managing agency) before you go.