Top 10 Glaciers in the United States
The United States has more glacier ice than any country outside the polar regions and a select group of mountain nations, with approximately 27,000 km2 of glaciers concentrated almost entirely in Alaska. The contiguous 48 states have a much smaller glacier inventory — primarily in Montana and Washington — but it includes some of the most scientifically monitored and publicly visited glaciers in the world, and the Glacier National Park record has become one of the most cited case studies in glacier retreat globally.
1. Bering Glacier, Alaska
The Bering Glacier system, including the Bagley Icefield that feeds it, is the largest glacier in North America at approximately 5,175 km2. It descends from the Saint Elias Mountains to the Gulf of Alaska coast near Cordova, terminating in a moraine-dammed proglacial lake. The Bering surges periodically — roughly every twenty years — advancing rapidly and then retreating. The last major surge was in the 1990s. The glacier is not easily accessible from the road system; overflights from Cordova or Yakutat provide the primary viewing opportunity.
2. Hubbard Glacier, Alaska
The Hubbard Glacier, calving into Disenchantment Bay near Yakutat, is the longest tidewater glacier in North America at approximately 122 km. Unusually, it has been advancing over recent decades rather than retreating. In 1986 and again in 2002, the glacier advanced far enough to temporarily seal off Russell Fjord from Disenchantment Bay, creating a glacially dammed lake until the ice dam failed. The calving face is approximately 10 km wide and 90 metres above the waterline. Cruise ships and small expedition vessels visiting Yakutat Bay bring the Hubbard within reach of Alaska cruise itineraries.
3. Margerie Glacier, Alaska
The Margerie Glacier in Tarr Inlet, Glacier Bay National Park, is the most visited actively calving tidewater glacier front in the United States. It is approximately 34 km long with a 97-metre-high calving face. National Park Service regulations limit vessel approach distance, but even from the permitted viewing zone, calving events — which occur several times per hour — are dramatic. The adjacent Grand Pacific Glacier, which retreated up-fjord to reveal the entire 50 km length of Tarr Inlet over the last 250 years, provides the geological context for the rapid deglaciation of the Glacier Bay system.
4. Knik Glacier, Alaska
The Knik Glacier flows from the Chugach Mountains into the Knik River valley northeast of Anchorage. It covers approximately 360 km2 and has been retreating steadily. The Knik River valley is accessible from the Glenn Highway; off-road vehicle tours and guided glacier treks operate from the valley floor. The glacier has a history of producing glacial lake outburst floods from ice-dammed George Lake; flood-monitoring infrastructure is maintained for the communities downstream.
5. Matanuska Glacier, Alaska
The Matanuska Glacier is the most accessible large glacier in Alaska, reachable from the Glenn Highway (Route 1) about 160 km northeast of Anchorage. The glacier is approximately 45 km long and 6 km wide at its terminus. Private land at the glacier toe allows walk-on access via paid entry; guided glacier walks and ice climbing excursions operate from the access road. The Matanuska is a valley glacier without tidewater dynamics, terminating on dry land above the Matanuska River.
6. Exit Glacier, Alaska
Exit Glacier in Kenai Fjords National Park, accessible by road from Seward, is one of the few glaciers in Alaska with a maintained interpretive trail to the ice margin. The 1.8 km return trail from the Nature Center reaches the ice face, with marker posts showing the glacier's former positions as far back as 1815. The Exit Glacier has retreated approximately 3.5 km since 1815. The adjacent Harding Icefield Trail climbs 600 m through forest and moraine to the icefield edge, offering panoramic views across the Harding Icefield — one of the largest in North America at approximately 2,700 km2.
7. Grinnell Glacier, Montana
The Grinnell Glacier in Glacier National Park is one of the most documented retreat stories in the world. When the park was established in 1910, it had approximately 150 named glaciers; as of 2022, approximately 25 active glacier bodies remain. Grinnell Glacier specifically covered 142 hectares in 1966 and had shrunk to approximately 17 hectares by 2020 — an 88% loss in 54 years. At current rates of warming, glaciologists project the park may lose its last permanent glaciers before 2080. The trail to Grinnell Glacier from Many Glacier Hotel is 11 km return (with optional boat shortcut on Lake Josephine) and is the most popular glacier hike in the contiguous United States.
8. Sperry Glacier, Montana
The Sperry Glacier in Glacier National Park sits in a high cirque accessible from the Sperry Chalet (a backcountry lodge, reservation required). At approximately 99 hectares as of 2022, it is slightly larger than Grinnell but similarly retreating. The chalet approach is a 14.5 km trail from Lake McDonald Lodge with approximately 1,600 m of elevation gain. The Sperry Glacier has retreated to the upper cirque from a much more extensive former extent that covered the Sperry basin.
9. Mendenhall Glacier, Alaska
The Mendenhall Glacier flows from the Juneau Icefield to within 19 km of downtown Juneau, making it one of the most city-accessible glaciers in the world. The Mendenhall Glacier Visitor Center (a US Forest Service facility) provides a free viewing platform; several trails reach the moraine and, in recent years, the accessible ice caves formed in the calving front. The glacier has retreated approximately 4 km since 1958. The ice caves within the glacier's calving face have become extremely popular, though their access changes each year as the ice moves and the caves evolve. The calving front drops into Mendenhall Lake.
10. Worthington Glacier, Alaska
The Worthington Glacier near Valdez is a cirque-valley glacier visible directly from the Richardson Highway (Route 4). A short paved path from the highway reaches the glacier toe — one of the most effortless glacier access points in Alaska. The glacier covers approximately 7 km2 and is set in a spectacular cirque below the Chugach Mountains. The Valdez glacier system nearby drains into Prince William Sound, where the 1989 Exxon Valdez spill occurred.
Glacier National Park: a monitoring case study
The USGS Northern Rocky Mountain Science Center has maintained a photographic and area-measurement record of Glacier National Park's glaciers since 1966. The repeat photography program, comparing historical photographs with current images from identical viewpoints, provides one of the most visually compelling public records of glacier retreat available anywhere. The USGS data is publicly accessible and is frequently used in climate communication.
Find US glaciers on the map
All glaciers in this list are plotted on the interactive map. Filter to the United States to see the concentration in Alaska and the smaller but intensively monitored glaciers of Montana.