What Heart Lake Offers

Heart Lake sits at 9,600 feet in the Sierra Nevada backcountry, about 10 miles from Mammoth Lakes town. The hike is a steady climb through lodgepole pine forest that opens onto alpine meadow, ending at a small, cold lake shaped roughly like its name. The water is too cold for swimming most of the year, but the lake sits in a granite bowl with views east toward the White Mountains, and the meadow around it holds wildflowers through mid-August.

This is not a casual walk. The trail gains roughly 1,500 feet over 5 miles, and the last mile crosses open terrain where afternoon thunderstorms can move in fast. Most people hike it as a day trip from the Mammoth Lakes area, though backpackers sometimes camp in the meadow and push on to other lakes in the Mammoth Lakes Wilderness.

The lake itself is small — you can walk around it in 20 minutes — but the hike rewards the effort. On a clear morning, the granite peaks and the quiet make the climb feel worth the work.

Key Takeaways

  • Heart Lake is a 10-mile round-trip day hike from Mammoth Lakes that climbs 1,500 feet to a high-country lake at 9,600 feet.
  • The trail starts at Lake George trailhead and follows lodgepole forest before opening onto alpine meadow in the final miles.
  • Afternoon thunderstorms are common in summer, so start early and plan to be off the open ridge by early afternoon.
  • The lake is too cold for swimming, but the meadow and granite views make it a solid destination for day hikers with moderate fitness.
  • Water from the lake requires treatment before drinking; bring a filter or purification tablets.

Getting to the Trailhead

Heart Lake trailhead is at Lake George, a small lake about 4 miles northwest of Mammoth Lakes town. From the town center, take CA-203 west toward Mammoth Mountain Ski Resort, then turn left on Lake Mary Road. Follow Lake Mary Road past Lake Mary itself — the road is paved and well-marked — and continue to the Lake George parking area at the end of the road.

The parking lot fills on weekends and summer weekdays, especially before 8 a.m. There is no shuttle service to this trailhead, so arriving early is the only way to may provide a spot. If the lot is full, you will need to return later or choose a different hike in the area.

The drive from town takes about 20 minutes. There is no fee to park or hike, and the trailhead is open year-round, though snow blocks the trail from November through May most years.

The Trail Itself

The hike starts at Lake George and immediately begins climbing through dense lodgepole pine forest. The first 2 miles are steep but shaded, and the trail is well-maintained and easy to follow. You will pass a few small streams — these run year-round but are often dry by late August.

At around 2.5 miles, the forest opens and you enter the meadow. The trail becomes less obvious here because it crosses open ground, but cairns (stacked rocks) mark the way. This is where the views open up: you can see the White Mountains to the east and the Sierra crest to the west. The final mile is the steepest, climbing through sagebrush and granite to the lake.

The entire hike is above 9,000 feet, so the air is thin. Even strong hikers feel the altitude. Take breaks, drink water, and do not push hard on the descent — your knees will thank you.

Weather and Timing

Summer afternoons bring thunderstorms almost daily in July and August. Lightning strikes the high ridges regularly, and the open meadow offers no shelter. The rule is simple: start before dawn or very early morning, and plan to be back at the car by 2 p.m. If you see clouds building over the ridge, turn around immediately, even if you have not reached the lake.

The best weather window is June and early July, when storms are less frequent and snow has cleared the trail. August is also hikeable but the storms are more reliable. September can be excellent — fewer people, clearer skies, and the first snow on the peaks — but nights are cold and the trail can be icy at dawn.

Winter snow closes the trail from November through May. Spring hikers should check current conditions with the Mammoth Lakes Visitor Center before driving out; the road to Lake George can be gated if snow is heavy.

What to Bring and How to Prepare

This is a high-altitude hike with no water sources near the trailhead and limited shelter. Bring at least 3 liters of water per person — the lake water requires treatment before drinking. A water filter or purification tablets are essential if you plan to refill along the way. Sunscreen, a hat, and sunglasses are not optional; the sun at 9,600 feet burns fast.

Wear layers. The morning can be cold, the midday sun hot, and the wind on the ridge sharp. A light rain jacket fits in a pack and can save a hike if weather turns. Sturdy hiking boots are better than trail runners on the rocky descent.

If you have not hiked above 9,000 feet recently, take it slow. Altitude sickness is real, and the best cure is descending. Headache, nausea, or shortness of breath that does not improve with rest means turning around.

Alternatives and Nearby Options

If Heart Lake feels too steep or the weather is poor, Lake George itself is a shorter option — the lake sits at the trailhead and offers views without the climb. Mammoth Crest Trail, which starts nearby, is a longer ridge walk with different views but similar altitude and exposure to afternoon storms.

For a less strenuous day, Horseshoe Lake is closer to town and lower in elevation, though it is also more crowded. The Mammoth Lakes Basin holds a dozen lakes within a few miles of town, each with different difficulty and scenery. The Visitor Center can suggest alternatives based on your fitness and the day's weather.

Frequently Asked Questions

Can I bring my dog on this hike?

Dogs are allowed on the trail and at the lake, but the altitude and rocky terrain are hard on paws. Bring extra water for your dog, and watch for signs of exhaustion. The descent is especially tough on joints.

Is there cell service at Heart Lake?

Cell service is spotty and unreliable above 9,000 feet. Do not count on your phone for emergencies. Tell someone where you are going and when you expect to return.

What is the best time of day to start the hike?

Start before 7 a.m. to beat the afternoon storms and the afternoon heat. An early start also means the parking lot is more likely to have space, and you will have time to turn around if weather or altitude becomes a problem.

Can I camp at Heart Lake?

Camping is allowed in the Mammoth Lakes Wilderness, but there are no established campsites at Heart Lake itself. Backpackers typically camp in the meadow below the lake or continue to other lakes in the wilderness. You will need a wilderness permit from the Mammoth Lakes Ranger Station.

How much time should I plan for this hike?

Most people take 4 to 5 hours round-trip, including time at the lake. Faster hikers can do it in 3.5 hours; slower hikers or those with altitude sensitivity may need 6 hours. Plan for a full morning and early afternoon.