Broad-tailed hummingbird
Selasphorus platycercus
Distinctive wing-trill of the breeding males in the wildflower basin June through August.
Photo: USFWS — public domain
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Indian Peaks · Hard
Diamond Lake
Alpine basin and waterfall via the Arapaho Pass Trail
Indian Peaks Wilderness
Distance5.4mi round trip
Elevation875ft gain
High point10,940ft summit
Typical time3–4.5hours
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Alpine basin and waterfall via the Arapaho Pass Trail. Editorial intro forthcoming.
Trip facts
Typical duration3–4.5hours
Trailhead10,100ft elevation
High point10,940ft summit
Dogs: leashes required.
How you'll find it
From Nederland, take CO-119 south 0.5 miles, turn west onto Boulder County Road 130 toward Eldora. Continue through Eldora; pavement ends, follow the rough dirt road 5 miles to the Fourth of July Trailhead. Free parking — arrive before 6am summer weekends.
Drive time
Personalize with your ZIP
We'll calculate drive time + a leave-by recommendation to beat the lot fill.
What you'll get
- 10,940ft alpine lake reached via the Arapaho Pass Trail
- Trail crosses a scenic waterfall on the North Fork of Middle Boulder Creek
- Less-crowded alternative to Brainard's lakes — no permit, no shuttle
- Wildflower-laden meadows in late July; basin frames Mount Neva to the west
- Pairs naturally with Arapaho Pass and Lake Dorothy for a longer alpine day
What locals know
Practical-craft notes for this specific trail — timing, route, photo, etiquette.
Trail tips
- Route
Loses 500ft before climbing — surprise descent on return
The trail drops 500ft from the Fourth of July Trailhead before climbing to Diamond Lake. The return is 500ft of UP-after-tired. Pace accordingly; many hikers underestimate the climb back.
- Photo
Waterfall on the North Fork — bring ND filter
The Middle Boulder Creek waterfall mid-trail is the classic Diamond Lake shot. A 6-stop ND filter at f/16 gives the silky-water look. Tripod required.
- Gear
High-clearance vehicle for the access road
The 5-mile dirt road past Eldora is rough — high-clearance recommended. 2WD sedans make it in dry conditions but get scraped underneath. 4WD recommended after rain.
- Timing
Quiet alternative to Brainard's permit system
No permit required (free trailhead) makes Diamond Lake the obvious Indian Peaks alternative when Brainard sells out. The trade-off is the rough access road and pre-6am parking pressure.
- Weather
Creek crossing high in spring runoff
The Middle Boulder Creek crossing runs high May–June from snowmelt. Plan for wet feet or use a downstream log crossing. By July it's manageable.
Where you'll start
Fourth of July Trailhead is free + no permit required — but the lot is small and the rough dirt-road approach makes it 90+ minutes from Boulder. Plan to arrive by 6am on summer weekends or expect to walk the access road. High-clearance vehicle preferred for the last 5 miles. Overnight allowed for wilderness-permit holders.
Parking cost
Free
Overnight
Allowed
Overnight allowed for backpacking permit holders entering Indian Peaks Wilderness — register at trailhead kiosk.
Park entrance
Free
Restrooms
Vault toilets
Fills by
6am summer weekends — extremely competitive, walk-the-road if you arrive late
Cell service
No signal
What's at the trailhead
- Restrooms — Vault toilets
- No potable water — bring your own from town
- Information kiosk
- No cell service — share plans + ETA with a contact before driving in
If the lot is full
Once the lot is full, hikers park along the access road below the trailhead and walk the final stretch — adds up to a mile of road walking each way on busy summer weekends.
Access road
The final 5 miles past Eldora are rough dirt — high-clearance vehicle strongly preferred. Most sedans can make it in dry conditions but expect a slow, bumpy drive. 4WD recommended after recent rain.
Vehicle security
Moderate break-in risk reported — stash valuables out of sight before arriving.
When to go
Highlighted months offer the best conditions.
Who shares the trail
Diamond Lake's wildflower basin draws hummingbirds and butterflies in late July; the surrounding talus hosts marmots and pikas through summer. Moose and mountain goats both possible — sightings increase mid-summer when alpine forage peaks.
- Common
CommonYellow-bellied marmot
Marmota flaviventris
MorningMiddayAfternoonPhoto: USFWS — public domain
CommonAmerican pika
Ochotona princeps
MorningMiddayAfternoonPhoto: NPS Photo, Rocky Mountain NP — public domain
OccasionalMoose
Alces alces shirasi
DawnDuskPhoto: NPS Photo — public domain
What to watch for
What to watch for
- Trail loses 500ft then climbs — tired hikers underestimate the return ascent
- Creek crossing on Middle Boulder Creek's North Fork high in early season
- Afternoon lightning at 11,000ft+ — turn back if storms build by noon
- Moose and mountain goat habitat — give wildlife 25+ yards
- Trailhead road rough on low-clearance vehicles — high-clearance preferred
On the map
Overnight camping
Indian Peaks Wilderness permit covers Diamond Lake camping. The basin's flat areas south of the lake make legal dispersed sites. Less popular than Lake Isabelle, so permits often available even on short notice.
Type
Dispersed backcountry
Water source
Middle Boulder Creek throughout; Diamond Lake at the destination.
Food storage
Bear-resistant canister REQUIRED.
Fire policy
Above treeline — stoves only. Below: established fire rings only.
Trail-tested picks for Diamond Lake
Curated for this trail's terrain, elevation, and typical conditions.
More routes from the same lot
Same parking, same logistics — if your plans need to flex, here's what else is reachable from Fourth of July Trailhead.
More Colorado trails
Lake Dorothy
Hard · Indian Peaks · 7.1 mi · 1,945 ft gain
The Indian Peaks' highest named lake at 12,061ft via Arapaho Pass
Read the guide →Lake Isabelle
Moderate · Indian Peaks · 4.6 mi · 440 ft gain
Alpine basin under Navajo Peak — 4.6 mi RT from Long Lake Trailhead
Read the guide →Mitchell Lake
Moderate · Indian Peaks · 1 mi · 230 ft gain
A half-mile walk into the Indian Peaks Wilderness
Read the guide →