What You'll Find at Emerald Lake

Emerald Lake sits at 9,400 feet in the Sierra Nevada backcountry, about eight miles southwest of Mammoth Lakes. The lake earned its name honestly — the water runs a vivid blue-green, especially on clear days when the granite peaks around it throw sharp shadows across the surface. You're fishing for cutthroat trout, mostly in the 8- to 12-inch range, with occasional fish pushing 14 inches if you're patient and the season has been kind.

The hike in is moderate but steady, gaining roughly 1,500 feet over those eight miles. The trail follows Emerald Lake Creek through lodgepole and whitebark pine, crossing meadows where the water slows and widens. Most anglers reach the lake in three to four hours, which means you can fish the afternoon and evening without a backpack camp, though many choose to stay overnight and fish dawn and dusk when the cutthroats feed most actively.

The lake itself is roughly 15 acres, with shallow bays on the north and east shores where aquatic insects hatch in summer and early fall. The south and west sides drop off quickly into deeper water. That depth variation matters — it's where the fish move as water temperature and light change through the day.

Key Takeaways

  • Emerald Lake requires a wilderness permit from the Inyo National Forest, which you can reserve online or pick up at the Mammoth Lakes Visitor Center the day before your trip.
  • The cutthroat trout here respond well to small dry flies (size 16–20) in late morning and evening, and to nymphs fished near the inlet creek during midday.
  • The trail is snow-free from late June through September, though snow can linger into early July depending on the year.
  • Emerald Lake sits above 9,000 feet, so altitude affects both your body and your fishing — plan for shorter casts and slower insect activity than you'd see at lower elevations.

Getting There and Permits

The trailhead is at Lake George, about seven miles west of Mammoth Lakes on CA-203 (Mammoth Scenic Loop Road). The parking area is small — 15 to 20 spaces — and fills by mid-morning on summer weekends. Arrive early or plan a weekday trip. The road is paved all the way, and the parking area has vault toilets but no water or services.

You need a wilderness permit from the Inyo National Forest. Day-use permits are free and can be picked up at the Mammoth Lakes Visitor Center (2510 Main Street, Mammoth Lakes) during business hours, usually 8 a.m. to 5 p.m. If you're staying overnight, you'll need a backcountry permit, which requires a reservation. The Inyo National Forest takes reservations online at recreation.gov starting five months in advance. Overnight permits cost $5 per person per night.

The trail itself is well-maintained and marked. Water is available from Emerald Lake Creek along the route, so you don't need to carry all your water from the trailhead — a significant advantage on a high-altitude hike.

What Flies and Tackle Work Here

Cutthroat trout at Emerald Lake are not selective, but they are small-water fish. Bring a 3- or 4-weight rod — anything heavier is overkill and makes casting in the wind more difficult. A 7.5-foot rod is ideal; longer rods catch more air on the exposed shorelines. Bring a floating line and a sink-tip line if you have one, though floating will handle most of your fishing.

Dry flies work best in the last two hours before sunset and the first two hours after sunrise. Stick to small patterns: Parachute Adams in size 16 or 18, Elk Hair Caddis in tan or olive, and small Stimulators. The cutthroats will rise to these, especially near the inlet where the creek enters the lake. During midday, when the sun is high and the water is flat, switch to nymphs — Pheasant Tail, Hare's Ear, and small Copper Johns in sizes 16 to 18, fished on a 9-foot leader with a 5X or 6X tippet.

The inlet creek is the most productive water. Fish will stack up there in the morning and evening, and the current helps them find food. Wade slowly and cast upstream, letting the nymph drift naturally. If you're fishing dries, cast to the seams where fast water meets slower water.

Timing Your Trip and Seasonal Conditions

Emerald Lake is fishable from late June through September. Snow typically blocks the trail until late June, though in heavy snow years the trail can remain impassable into early July. Check with the Mammoth Lakes Visitor Center or the Inyo National Forest website before you go — they post trail conditions regularly.

July and August are the warmest months and the busiest on the trail. The lake is fully thawed, water temperatures are stable, and insect hatches are predictable. September is often the best month for fishing: fewer people, cooler water that keeps the fish active all day, and strong mayfly and caddis hatches in the afternoon.

Afternoon thunderstorms are common in July and August, especially between 2 p.m. and 5 p.m. They can be violent and brief. Start your hike early, fish the morning and early afternoon, and be off the exposed ridges by mid-afternoon. Lightning is a real hazard at this elevation.

Altitude and Physical Preparation

At 9,400 feet, Emerald Lake sits high enough that altitude affects most people who live at sea level or low elevation. The hike gains 1,500 feet, which is moderate, but the thin air makes it feel steeper than the grade suggests. Take your time, drink water constantly, and don't push hard on the first day if you've just arrived in Mammoth.

Altitude also affects your fishing. Your casting distance will be shorter — the air is thinner, so your line doesn't carry as far. Insects hatch later in the day and in smaller numbers than they do at lower elevations. Fish are less aggressive, so smaller flies and longer leaders work better. Plan for slower fishing than you might expect, and you'll be pleasantly surprised when the cutthroats cooperate.

Bring sunscreen and a hat. The sun is intense at this elevation, and the granite reflects it back at you. Dehydration happens fast, even when you don't feel thirsty.

Where to Fish on the Lake

The inlet creek, where Emerald Lake Creek enters from the north, is the most reliable spot. Fish will be there in the morning and evening, and often during midday if the sun isn't too bright. Wade carefully — the bottom is rocky and uneven — and cast upstream into the current.

The shallow bay on the east shore, near the outlet, holds fish in the afternoon when they move out of deeper water to feed. This is a good place to fish dries in the late afternoon. The water is clear, so keep your distance and use a long leader.

The deeper water on the south and west sides is less productive for sight-casting, but if you're fishing nymphs on a sink-tip line, you can cover it systematically. Fish will be deeper here during the heat of the day, especially if the sun is bright.

What to Bring and Leave Behind

Pack light. You're carrying everything eight miles in and eight miles out. Bring your rod, reel, and tackle in a small pack or chest pack. Leave the heavy fly box at home — bring only the patterns you'll actually fish. A small net is useful for landing fish, but not essential. A headlamp is important if you plan to fish into dusk or camp overnight.

Bring a water filter or purification tablets. The water is generally clean, but giardia is present in high alpine lakes, and filtering is safer than trusting your luck. Bring a lightweight rain jacket — afternoon storms can drop the temperature 20 degrees in minutes. Wear layers; the morning is cold, midday is warm, and evening is cold again.

Leave behind anything you don't need. Every ounce matters on a long hike. Ultralight gear — a small pack, minimal clothing, a lightweight rod — makes the trip more enjoyable and leaves you with more energy for fishing.

Frequently Asked Questions

Do I need a backcountry permit if I'm just day-fishing?

No. Day-use permits are free and available at the Mammoth Lakes Visitor Center. You can pick one up the morning of your trip or the day before. If you're camping overnight, you need a backcountry permit with a reservation, which costs $5 per person per night.

Can I fish Emerald Lake in June or October?

The trail is usually snow-free by late June, but conditions vary by year. Call the Mammoth Lakes Visitor Center to check trail conditions before you go. October can be fishable, but snow can return early, and nights are very cold. September is more reliable.

What's the best time of day to fish?

Early morning (sunrise to 10 a.m.) and evening (4 p.m. to sunset) are most productive. Midday is slower, but you can still catch fish on nymphs near the inlet. Afternoon thunderstorms often shut down the bite, so plan to be off the water by mid-afternoon.

Is the hike difficult for someone who doesn't backpack often?

The hike is moderate — eight miles and 1,500 feet of elevation gain — but the altitude makes it feel harder than the numbers suggest. Take your time, bring plenty of water, and don't rush. Most people reach the lake in three to four hours. If you're not used to hiking, plan for four to five hours.

Can I fish Emerald Lake with a spinning rod?

Yes. Small spinners and spoons work, though fly fishing is more effective in this clear, shallow water. If you use spinning gear, bring ultralight lures — 1/32 to 1/16 ounce — and expect to lose some to the rocky bottom.