Grinnell Glacier Is 10 Miles of Trail to Ice That's Half Gone

The trail's last move is a staircase of glacial rubble, and it hides the payoff until the final step. Then the moraine crests and the basin opens: a lake the color of weathered turquoise, rafted with icebergs into late summer, pressed against two thousand feet of layered stone. The shelf of ice at the far shore is Grinnell Glacier. The lake it calves into is so young that a 1940 photograph shows it just beginning to form.

George Bird Grinnell hiked up to this ice in 1887 with a camera and guessed at what he was standing under — "the thickness of this mass of ice can scarcely be less than 100 feet and may be much more." The U.S. Geological Survey has been measuring it ever since, and the arithmetic runs one direction: roughly 530 acres in 1900, 252 in 1966, 139 by 2015. Nearly half the glacier's remaining area has vanished in the span of a single lifetime, and USGS modeling projects the park's glaciers will be essentially gone by 2100 no matter which emissions future arrives. That is what makes this the most-watched five miles of trail in Montana: it ends at a clock.

• Trailhead: Grinnell Glacier Trailhead in the Many Glacier valley, or the dock behind the Many Glacier Hotel
• Round trip: 10.6 miles on foot; 7.2 miles using the boat shortcut (NPS)
• Elevation gain: about 1,600 feet to the glacier viewpoint — the park's cumulative count runs closer to 2,600
• The boat: Glacier Park Boat Company crosses Swiftcurrent Lake and Lake Josephine on two historic boats; adult round trip $41.70 in 2026, season June 10 – September 19, reservations strongly recommended
• Bears: both grizzly and black bears live here — carry bear spray, hike in groups, make noise (NPS)
• 2026 access: no vehicle reservations anywhere in Glacier this year, and the Many Glacier construction is finished — the rebuilt Swiftcurrent area has 339 parking spaces, 171 more than before
• The ice: Grinnell Glacier lost 113 acres between 1966 and 2015 (NPS); USGS modeling projects near-total glacier disappearance in the park by 2100

Two lakes before the wall

The first three miles barely climb. From the trailhead the path crosses the outlet at Swiftcurrent Lake's southwest corner, then traces the northwest shore of Lake Josephine, with Grinnell Point stacked overhead and the Garden Wall — the serrated spine of the Continental Divide — filling the view ahead. It is the gentlest opening act of any major hike in the park, and it is also optional.

Since 1960, wooden tour boats have run these two lakes as a relay: the Chief Two Guns crosses Swiftcurrent Lake, a 0.2-mile walk hops the ridge between the lakes, and the Morning Eagle — built in 1945 — finishes the run down Josephine. Hikers ride out in about 45 minutes and step off 1.7 trail miles closer to the glacier, cutting the round trip from 10.6 miles to 7.2. In 2026 an adult round trip is $41.70, the season runs June 10 to September 19, and reservations are strongly recommended — the boats fill like the parking lots do.

About those parking lots: this is the summer to come. The construction that restricted Many Glacier access in 2025 is finished — the park's February 2026 update says plainly that construction "is completed and not anticipated in the Many Glacier area in 2026" — and the rebuilt Swiftcurrent area now holds 339 vehicles, 171 more than before. Parkwide, Glacier dropped vehicle reservations entirely for 2026. The valley still fills by mid-morning in July and August; the era of needing a reservation, a shuttle ticket, and luck to get here is, for now, over.

A ledge across the Garden Wall

Past the head of Lake Josephine the trail turns uphill and stays there: 1,600 feet of climbing, most of it on an open ledge cut across the flank of the Garden Wall. The park's description is two words long — "mostly exposed" — and both words earn their keep. The tread is wide but the dropoffs are real, snow can hold on the ledge into July, and there is no shade worth the name after the junction.

What the exposure buys is the finest sustained view on any day hike in the park. Grinnell Lake sits five hundred feet below the trail, an implausible milky turquoise — rock flour, ground from the mountain by the ice above and suspended in the meltwater. Grinnell Falls threads the headwall behind it. Wildflowers crowd the tread in July, and the cliffs above are working terrain for bighorn sheep and mountain goats.

It is also, unambiguously, bear country. Glacier supports nearly a thousand black and grizzly bears, and Many Glacier is their stronghold — trail closures for bear activity are a routine fact of the valley. The park's playbook is short: hike in groups, make noise around corners and creeks, carry bear spray where you can reach it, and if you meet a bear, do not run. Treat the current trail status report as part of the route.

The ice at the end

The final mile switchbacks up the moraine — the pile of rubble the glacier itself bulldozed when it was still advancing — and tops out at the overlook beside Upper Grinnell Lake. The scene reads like geology on fast-forward. A 1940 photograph from this vantage shows the lake in its "early formation"; USGS's 2013 repeat of the same frame shows open water where ice stood, the lake grown dramatically at the glacier's expense. The bergs drifting across it in August calved from the shelf on the far side. Above it all, pasted against the cliff, hangs the ice apron GNIS officially names The Salamander.

The numbers behind the view are the reason USGS keeps re-shooting it. Grinnell has surrendered 113 acres since 1966 — from 252 acres down to 139 by 2015, nearly half its area. It is not an outlier: across the 39 glaciers USGS mapped in Montana, the average loss since 1966 is 39 percent, with some ice bodies down 85 percent, and the count of park glaciers larger than a tenth of a square kilometer has fallen by nearly 60 percent since the Little Ice Age maximum around 1850. Measurements from the 1900s already caught the trend — between 1937 and 1969 alone, the terminus retreated nearly 1,200 feet while the ice surface dropped 25 to 30 feet.

None of this is abstract at the overlook. The glacier that helped talk a national park into existence is now the park's clearest measure of time running out — and the trail to it is, mile for mile, as beautiful as anything in the Lower 48.

The man the glacier is named for

George Bird Grinnell — editor of Forest and Stream, founder of the first Audubon Society — first came to this corner of Montana in 1885 and kept coming back nearly every year for the rest of his life. He saw the Many Glacier valley in 1886, packed a camera up to the ice the following summer, and then spent two decades doing something harder than the hike: convincing the country the place should be permanent. The National Park Service gives him the credit directly — "to Grinnell goes the credit, and justly so, for swinging public opinion in favor of making this area into a national park." President Taft signed the bill in 1910, and the glacier already carried Grinnell's name.

The photographs he started taking in 1887 became the baseline for one of the longest visual records of climate change in North America — USGS has built roughly sixty repeat-photography pairs in the park on exactly that model. Grinnell got a glacier named after him; the glacier got a century-long portrait series of its own disappearance.

Where this series goes next

This is the third article in our series on America's signature day hikes, after Angels Landing and its chains and Half Dome and its cables — single-day routes that earned national reputations, told with the route traced over real terrain. (For the strange mirror image of this story, read about the glacier that grew inside Mount St. Helens — America's youngest glacier, expanding while its most famous one melts.) Every mile of the line above is browsable on the Grinnell Glacier Trail page on Outdoors, alongside the rest of Glacier National Park's trails.

Sources

• Grinnell Glacier Viewpoint is 5.3 miles one-way (3.6 miles using the concession boat from Many Glacier Hotel) with 1,600 feet of elevation gain, from the Grinnell Glacier Trailhead or Many Glacier Hotel; boat tour fees apply and reservations are highly recommended — NPS, Hiking Many Glacier
• The trailhead page lists 5.0 miles one-way with 2,596 feet of cumulative gain and 1,015 feet of loss (boat dropoff: 3.7 miles, 1.3 miles closer); the hike is 'popular and mostly exposed' with steep dropoffs and wildlife awareness advised — NPS, Grinnell Glacier Trailhead
• Vehicle reservations are not required anywhere in Glacier National Park in 2026; Logan Pass moves to a ticketed shuttle system with three-hour timed parking — NPS, Vehicle Reservations
• Construction 'is completed and not anticipated in the Many Glacier area in 2026'; the rehabilitated Swiftcurrent area now has 339 parking spaces, an increase of 171 — NPS news release, 2026 Construction Updates in Glacier National Park (Feb 12, 2026)
• The Swiftcurrent water-system construction began in fall 2024 and ran through mid-May 2026; personal-vehicle access to Many Glacier was restricted with a temporary hiker shuttle July 1 – September 21, 2025 — NPS news release (Jan 16, 2025)
• The Many Glacier boat tour crosses Swiftcurrent Lake on the Chief Two Guns and Lake Josephine on the 1945-built Morning Eagle, linked by a 0.2-mile walk; outbound trip about 45 minutes; 2026 adult round trip $41.70, season June 10 – September 19; prices approved by the National Park Service — Glacier Park Boat Company
• Waterton-Glacier is home to both black and grizzly bears — nearly 1,000 bears; hiking in groups significantly decreases negative encounters, bear spray has been shown to be the most effective deterrent, and if you encounter a bear: do not run — NPS, Bear Safety
• Grinnell Glacier lost 113 acres between 1966 and 2015; the park's glaciers were largest at the end of the Little Ice Age (around 1850) — NPS, Climate Change in Glacier
• USGS's 1966–2015 margin data: Grinnell Glacier shrank from 1.0202 km² (252 acres) in 1966 to 0.5637 km² (139 acres) in 2015 — a 44.7% loss, 71% below its Little Ice Age extent — USGS, Table of Area of the Named Glaciers
• The 39 Montana glaciers USGS mapped have shrunk an average of 39 percent since 1966, some by as much as 85 percent; only 26 remain larger than 25 acres — USGS news release, May 10, 2017
• The number of park glaciers larger than 0.1 km² has decreased by nearly 60% since the mid-19th-century Little Ice Age maximum; physical modeling predicts near-total glacier disappearance by 2100 regardless of emissions pathway; USGS maintains about sixty repeat-photography pairs — USGS, Status of Glaciers in Glacier National Park
• Grinnell Glacier decreased from about 530 acres in 1900 to 298 acres in 1966 (earlier-methodology series); between 1937 and 1969 the terminus receded nearly 1,200 feet and the ice surface lowered 25–30 feet — USGS Professional Paper 1180 (Johnson, 1980)
• A circa-1940 photograph shows the early formation of Upper Grinnell Lake at the glacier terminus; the 2013 repeat shows a dramatic increase in the lake's size as a result of melting ice — USGS, Grinnell Glacier Overlook 1940–2013
• George Bird Grinnell first came to the area in 1885, saw the Many Glacier Valley in 1886, photographed the glacier in 1887 and estimated the ice 'can scarcely be less than 100 feet' thick; NPS credits him with 'swinging public opinion in favor of making this area into a national park,' signed into law by President Taft in 1910 — NPS, People of Glacier + Repeat Photos of Grinnell Glacier
• Route geometry: Swiftcurrent Lake Trail, North Shore Josephine Lake Trail, and Grinnell Glacier Trail ways, © OpenStreetMap contributors (ODbL)

Keep reading

• Half Dome: the permits, the cables, and how the hike works
• Angels Landing: the permit, the chains, and the fin
• The glacier that grew inside Mount St. Helens

Hero photograph: Upper Grinnell Lake at the end of the trail — meltwater, icebergs, and the shrinking shelf of Grinnell Glacier. by National Park Service, licensed under Public domain (NPS photo).