What to expect at Butterfly Lake

Butterfly Lake sits at roughly 10,700 feet in the Uinta Mountains, about 45 minutes northeast of Kamas. The lake holds native cutthroat trout and introduced brook trout, both of which grow to catchable size in the cold, clear water. It's a backcountry destination — no motorboats, no developed facilities — which means the hike in keeps crowds manageable and the fish less pressured than at roadside reservoirs.

The trail to Butterfly Lake is roughly 7 miles round trip from the Mirror Lake trailhead, gaining about 1,500 feet. Most anglers reach it in three to four hours. The lake itself is small, maybe 10 acres, with shallow bays on the north end and deeper water along the eastern shore. Cutthroat tend to hold in the deeper sections; brook trout scatter throughout but concentrate near inlet streams.

Summer is the only realistic season. The lake remains frozen or nearly frozen until late June, and snow can return by early September. July and August are prime months. Water temperature peaks in the mid-60s Fahrenheit — cold enough that fish feed throughout the day, not just at dawn and dusk.

Key Takeaways

  • Butterfly Lake holds native cutthroat and brook trout at 10,700 feet elevation, accessible only by a 7-mile round-trip hike from Mirror Lake trailhead.
  • The lake is open to fishing year-round under Utah Division of Wildlife Resources regulations, but snow and ice make access practical only from late June through early September.
  • No motors, no developed camping, and no services at the lake itself — bring all water, food, and gear you need for the day or overnight.
  • Cutthroat respond well to small spinners and dry flies; brook trout take wet flies, nymphs, and small spoons throughout the day.
  • A Utah fishing license is required; check current regulations for any species-specific restrictions or catch limits before you go.

How to reach Butterfly Lake

The trailhead is at Mirror Lake, on Utah State Road 150 (Mirror Lake Scenic Byway) in the Uinta National Forest. From Kamas, drive northeast on SR 150 for about 30 miles; the Mirror Lake parking area is on the right. The lot fills on summer weekends, especially Saturdays — arrive early or plan a weekday trip.

From the parking area, follow the Mirror Lake Trail north and west. The trail is well-marked and maintained but steep in sections. At roughly 3.5 miles, you'll reach a junction; turn left (south) toward Butterfly Lake. The final stretch descends slightly into a small basin where the lake sits. Total elevation gain is manageable for most hikers, but the altitude and distance mean you should plan a full day for the round trip.

Camping is allowed in the Uinta National Forest, but no developed sites exist at Butterfly Lake itself. Backpackers typically camp on the north or west shore, at least 100 feet from the water. Fires are prohibited above 10,000 feet in the Uinta Mountains, so bring a camp stove if you plan to cook.

Fish species and seasonal patterns

Cutthroat trout are the native species in Butterfly Lake. They average 8 to 12 inches, with occasional fish reaching 14 inches. Cutthroat are less aggressive than brook trout but more selective about presentation — they respond to small dry flies and spinners that mimic natural insects. In July and August, they feed most actively in the deeper water along the eastern and southern shores, particularly near the inlet stream on the north end.

Brook trout were introduced decades ago and now make up a significant portion of the catch. They're more aggressive than cutthroat and less picky about fly size or color. Brook trout school in shallower water and respond well to wet flies, nymphs, and small spoons. They feed throughout the day, making them a reliable target when cutthroat are inactive.

Early summer (late June through July) sees the most consistent fishing as the lake clears and water temperature stabilizes. August can be productive but sometimes slower as water warms slightly and fish move deeper. By late August, evening fishing often outperforms midday, as cooler temperatures trigger feeding activity.

Tackle and technique recommendations

Fly fishing is the most effective method at Butterfly Lake. A 4-weight or 5-weight rod with a floating line covers most situations. For cutthroat, carry small dry flies (size 16 to 20) in patterns like Adams, Pale Morning Dun, and Elk Hair Caddis. Nymphs in sizes 14 to 18 — Pheasant Tail, Hare's Ear, and small Prince Nymphs — work year-round and often outfish dries on cloudy days.

Brook trout take larger patterns more readily. Wet flies like Woolly Buggers (size 10 to 12) and small streamers produce strikes, especially if you strip them near structure or along drop-offs. A sinking line or sink-tip can help you reach deeper fish, though a floating line with a long leader works fine in the shallower bays.

Spin anglers should bring small spinners (size 0 or 1) in silver or gold, and small spoons in similar finishes. Cast near the inlet stream and along the eastern shoreline where cutthroat hold. Retrieve slowly — the cold water means fish aren't chasing fast-moving lures.

Regulations and permits

You must have a valid Utah fishing license to fish Butterfly Lake. Licenses are available online through the Utah Division of Wildlife Resources website, at sporting goods retailers, and at some gas stations. A one-day license costs less than a full-year license if you're visiting for a single trip.

Check the current Utah fishing guidebook for any species-specific restrictions. Catch limits and size restrictions vary by water and change periodically. As of recent years, Butterfly Lake has had liberal limits on both cutthroat and brook trout, but regulations do shift — confirm before you fish.

The lake sits in the Uinta National Forest, which has its own rules: no motors, no generators, and fires prohibited above 10,000 feet. Pack out all trash, including microtrash like small bits of line or fly material. The forest service asks that anglers stay on established trails to prevent erosion and protect alpine vegetation.

What to bring and how to prepare

This is a high-altitude, backcountry destination. Bring more water than you think you'll need — the hike gains elevation quickly, and dehydration at altitude happens fast. A hydration pack or water bottles totaling at least 2 liters is standard. Filter or treat any water you collect from the lake or streams.

Weather changes rapidly above 10,000 feet. Even in July, afternoon thunderstorms are common, and temperatures can drop 20 degrees in an hour. Pack a rain jacket and a fleece layer regardless of the forecast. Sunscreen and a hat are essential — the sun reflects off water and snow, and UV exposure is intense at altitude.

Wear sturdy hiking boots with good ankle support; the trail has rocky sections and loose scree. Trekking poles reduce strain on your knees on the descent. If you're backpacking, a lightweight tent rated for cold nights and a sleeping bag rated to at least 20 degrees Fahrenheit are wise — nighttime temperatures can dip below freezing even in August.

When to fish and what conditions favor success

July offers the most reliable fishing. The lake is fully accessible, water temperature is stable, and both cutthroat and brook trout feed actively. Overcast days often outfish sunny days — clouds reduce glare and trigger more feeding activity. Early morning (first two hours after sunrise) and evening (last two hours before sunset) are prime times, though fish feed throughout the day in the cold water.

Windy days can be frustrating for fly anglers but often improve fishing because wind breaks the surface and reduces the fish's ability to see your silhouette. Fish the lee shore (the side protected from wind) where insects accumulate and trout congregate.

Late August can be productive if you're willing to work harder. Fish move deeper and feed less predictably as water warms. Focus on the inlet stream and the deepest parts of the lake. Evening fishing becomes more important — plan to fish from 5 p.m. until dark for the best chance at active fish.

Frequently Asked Questions

Can I fish Butterfly Lake in winter?

Technically yes — the lake is open year-round under Utah regulations. Practically, no. Snow blocks the trail by September, and the lake freezes solid by November. Winter access requires snowshoes or skis and mountaineering skills. Most anglers fish only from late June through August.

How long does the hike take with a full backpack?

A 7-mile round trip with a loaded pack typically takes four to five hours for most hikers. The elevation gain is steady but not extreme. Start early — reaching the lake by early afternoon gives you time to set up camp and fish before dark.

Are there fish in the inlet stream?

Yes. The inlet stream holds cutthroat and brook trout, often in small pools and runs. Stream fishing can be productive, especially in early morning. Fish are smaller than lake fish but more numerous. Respect the 100-foot setback from the lake if you're camping nearby.

What's the difference between the cutthroat and brook trout at Butterfly Lake?

Cutthroat are native and more selective — they require smaller flies and more precise presentation. Brook trout are introduced and more aggressive, taking larger patterns and faster retrieves. Both are worth targeting; cutthroat offer a technical challenge, brook trout offer consistent action.

Do I need a bear canister or bear bag?

Bear encounters are rare at Butterfly Lake, but proper food storage is required in the Uinta National Forest. A bear canister or bear bag hung at least 12 feet high and 6 feet from tree trunks is standard practice. Check current forest service guidance before you go.