Colorado · Hiking · Near Idaho Springs

Lost Lake

Lost LakePhoto: toastal_OLD, CC BY 2.0 (via Flickr)
1.0 mi
round trip
215 ft
climb
9,823 ft
high point
Out and back
route
Jun, Sep
best months

Is Lost Lake open right now?

Alert in the area

The Forest Service lists 3 alerts for Arapaho and Roosevelt National Forests.

As of · Source: USFS · Arapaho and Roosevelt National Forests. Agencies don't list every closure — check before you go.

Lost Lake is an easy hike in the Boulder Ranger District of the Arapaho and Roosevelt National Forests in Colorado, about a mile from the town of Boulder. The Forest Service manages the land, and the trail is short and low, with a one-way climb of about 215 feet from a low point of 9,605 feet to a high of 9,823 feet. The trail is natural-surfaced and open to both horses and bikes, so it works for riders and equestrians as well as hikers. The route is out and back, and the whole trip is under a mile. Summer is the most comfortable time to go. Typical averages from a nearby weather station show July highs around 68°F with lows near 43°F, while winter highs stay in the 20s. Old Lost Lake, a mountain biking trail, sits just 0.1 mile away, and King Lake and the Eldora climbing area are each about 0.3 mile off. For an overnight stay, Rainbow Lakes Campground is about 4.5 miles away.

Around this trail

Add any of these when you start a trip
  • Sleep close

    Lost Lake Campground

    Campground

    Campground · 0.3 mi from the trail
  • Eat after

    Lookout Grill

    Restaurant

    On your way back · 1 mi

Places © OpenStreetMap contributors · Photos: Matt Golon, CC BY-SA 3.0 (commons)

More in Idaho Springs

Local outfitters

Not on Roamze yet. Their page has how to reach them.

  • Best time to go · Jun, Sep

    Best time to visit Lost Lake

    Best months: June and September. Best months have typical highs of 55–85 °F, lows of 30 °F or warmer (32 °F where the station doesn't record snow), at most one snowy day and no more than 12 wet days.

    1. Jan

      29° / 12°

      15 wet

    2. Feb

      28° / 11°

      16 wet

    3. Mar

      36° / 17°

      16 wet

    4. Apr

      40° / 22°

      17 wet

    5. May

      50° / 29°

      16 wet

    6. Jun

      62° / 36°

      12 wet

    7. Jul

      68° / 43°

      14 wet

    8. Aug

      66° / 41°

      13 wet

    9. Sep

      59° / 34°

      10 wet

    10. Oct

      47° / 26°

      10 wet

    11. Nov

      35° / 19°

      12 wet

    12. Dec

      28° / 12°

      15 wet

    Typical high / low (°F) and days with rain or snow, 1991–2020. Measured at Boulder 14 W, CO, 6.9 mi away at 9,828 ft. This station doesn't record snowfall. Source: NOAA NCEI U.S. Climate Normals 1991–2020.

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