Hike Mammoth Crest to Deer Lakes


Eastern Sierra, Hike Reports / Wednesday, September 23rd, 2020
HIKE TO: Deer Lakes, Duck Lake, Pika Lake, Barney Lake
TRAIL: Mammoth Crest to Duck Pass 
MILES: 16.44 miles
TIME: 7:17 hrs moving time (1 night)
DATE I WENT: 7/4/20 - 7/5/20
DIFFICULTY: moderate
ELEVATION: 11254 ft
ELEVATION GAIN/ LOSS: 3748 ft
HIKE PERMIT: yes for overnight backcounty camping, no for day hikes
PARKING PERMIT: no
LOCATION: Eastern Sierra/ Inyo National Forest/ Ansel Adams Wilderness

This loop tours the Mammoth Lakes area of Ansel Adams Wilderness and passes 17 alpine lakes. Most of these lakes are popular tourist destinations but Deer Lakes is less-trafficked and still very pristine so please do your part in recreating responsibly and Leave No Trace.

This trail can be done as a 16.4-mile loop in a day hike, overnight hike, or even just a 12.4-mile day hike to Deer Lakes which is what I did my first time here. If you want to camp at Duck Lake but couldn’t get permits, this trail allows you to camp there as well after your first night. Our planned trip was 2 nights: first night at Deer Lakes (as that’s what the permit was for), the second night at Pika/Duck Lake. But it was such as easy hike the second day that we just hiked out.

deer lakes basin

Backpacking Trip Report: Mammoth Crest Loop

The trail requires a little bit of cross-country hiking (no established trails/ route-finding).

[Saturday, July 4, 2020] The Mammoth Crest Trail Loop starts at the Crystal Lake trailhead for the first 1.1 miles and climbs about 700 ft in elevation before you reach a junction and continue right (going straight leads to Crystal Lake and the base of Crystal Crag Approach) for another 0.9 miles. As the trail continues to climb up higher and out of the town of Mammoth Lakes, the views open up and you will start to see the Mammoth Lakes basin which include: McCloud Lake, Horseshoe Lake, Lake George, Twin Lakes, Crystal Lake, Lake Mamie

2 miles from the trailhead, you’ll reach the top of that first section out of Mammoth Lakes Basin. From here, the crowds dissipate a ton. I’ve been up here twice and only saw two other people in the Summer and no one else in the Fall. The trail runs parallel with the JMT but never connecting.

Fun fact: up here, you’re by the junction and hike through three different counties: Mono County, Madera County, and Fresno County.

We had a leisurely morning and a late start on the trail at 12:20 pm but I felt so exhausted that we ended up taking a half hour food/ shade break.

2.4 four miles further and 835 ft elevation later (4.4 miles from the start), the trail tops out at 11,195 ft. The trail opens up to a chute on the left side with beautiful views of the wilderness encircled by this loop trail.

Deer Lakes which consists of 3 lakes: upper deer lake, middle deer lake, and lower deer lake. From the chute, you’ll get your first view of the lakes within 10 mins and then the trail becomes a little slipperier with tiny little rocks on the trail going down, descending 552 ft in 1.2 miles to reach the middle lake. Once you reach the middle Deer Lake, you’ll have to climb back up to get to the upper lake. At 6.2 miles from the trailhead sits Upper Deer Lake at 10986 ft, my favorite of the three and where we chose to camp.

We arrived at 4:20 pm, set up camp, took a short break inside away from the mosquitos, then headed for a quick evening dip at 5:40 pm before sun set and dinner. We were able to hang out in the lake for about 40 mins before getting eating alive by the mosquitos or sand flies (not sure what it was, I think it was sand flies just because I didn’t get the usual reaction I do from mosquitos).

We were back at camp by 6:30 pm. I made sure to pack the larger 3-door Big Agnes tent because I knew we would have plenty of time to just hang out and hide from the bugs, which worked out great with Kinga’s two small dogs. I also rarely pack a book but again, I knew I’d have extra time so I read a little, we made dinner, and came out to see the sunset glow from 8:10 – 8:20 pm.

Don’t forget a bear resistance container for proper food storage when camping – get my bear canister here.

[Sunday, July 5, 2020] The next morning was the worst bugs I have ever experienced. Waking up at the crack of dawn didn’t help at all with the bug situation and since it was supposed to be a short hiking day, we hid out in the tent until 10:20 am, quickly packed up, and were back on the trail by 10:40 am. I think the bugs were extra bad because we were by the lake (still far, but surrounded by greens and water). Once we started hiking towards the rocks, the mosquitos cleared up a lot.

Mosquitos season varies from year to year. This is what I've noticed in my recent years of hiking:
2020: early/ dry season - snow melts in May, mid-June through early/mid July is bad. Since late July, it's been good in our mountains.
2019: late season - snow melts mid/late July and late July was terrible bugs
2018: early/ dry season - snow melts mid-May, bugs were terrible in mid/late July but fine by second week of August
2017: I'm drawing a blank
2016: early June was terrible bug season and snow was still melting, don't remember much else

From Upper Deer Lake, you can either hike back the same way out for a 12.4-mile hike or do a little cross country hike to get over to Duck Lake and make it a longer 16-mile loop. We day hiked back out the first time we were here in September 2019 so we decided to hike the Mammoth Crest-Duck Lake Loop it this time. We weren’t quite sure where exactly the trail was from camp but luckily I had a GPX file to vaguely follow.

To connect Mammoth Crest to Duck Lake, the trail starts off on a short cross country trek over the mountains. It was only 20 mins to get up the scramble section and there’s a faintly-used trail. It’s only about half a mile to get to the highest point of the trail (11254 ft) and then the trail descends 0.73 miles to connect with Duck Lake Trail. Don’t forget to explore Pika Lake behind Duck Lake!

I did my first alpine lake plunge at Duck Lake! I’m a chicken for the cold water but this summer, I’ve been working on getting more comfortable in the water. I dipped into almost every alpine lake I’ve visited, swam in a few, and fully submerged in a handful of them – feeling kind of proud of myself

Carrying on – the trail from Duck Lake/ Pika Lake to Duck Pass to Barney Lake can be found on my older blog here.

From here you can either follow the short trail back to Duck Lake Pass trailhead at Coldwater Campground (if you’re with a group, leave one car at each trailhead for a slightly shorter trail – they’re very close to each other) or loop it back to the same trailhead you started at, Crystal Lake Trailhead.

barney lake in mammoth lakes

From Barney Lake, it’s 4.7 miles to loop back to Crystal Lake Trailhead at Lake George Campground.


From Barney Lake, it’s 2.4 miles to Duck Lake Pass Trailhead at Coldwater Campground (+2 miles to walk the road to Crystal Lake Trailhead if you don’t have a car shuttle in place).

If you hike the loop back to Crystal Lake Trailhead, you will pass a few more lakes along the way including Emerald Lake, Lake Barrett, and two unnamed lakes.

The Duck Lake wilderness permit can be hard to obtain as it’s a very popular trail in the Mammoth Lakes area, so hiking this loop will allow you to camp at Duck Lake (well Pika Lake or Barney Lake since you can’t camp right at Duck Lake) if you make it a 2+ night trip entering and passing through Deer Lakes.

followtiffsjourney purple sunday afternoon hat
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6 Replies to “Hike Mammoth Crest to Deer Lakes”

  1. Amazing pictures, great hike descriptions, thank you! It shows how much you enjoy it and how much you like swimming in those Alpine Lakes.

    1. Thank you Bernhard.Hope you’ll find it helpful when you come down to explore the beautiful Eastern Sierra mountains. Swimming in all these alpine lakes is a personal challenge I’ve been working on this year, getting comfortable with the cold and uncomfortable.

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