The largest glaciers in the United States are found almost entirely in Alaska, which boasts more glacial ice than the rest of the country combined—covering roughly 23,000 to 34,000 square miles depending on measurement methods. These massive ice bodies, including vast icefields and dynamic valley glaciers, shape dramatic landscapes, feed major rivers, influence local sea levels, and serve as vital indicators of climate change. Among the giants are the Bagley Icefield, often ranked as the largest by area at approximately 863 square miles, and the Bering Glacier, frequently described as North America’s largest or longest glacier when combined with its feeding icefield, spanning over 120 miles and part of a complex exceeding 1,900 square miles.
Other standout features include the Malaspina Glacier, North America’s largest piedmont glacier (where ice spreads out at the base of mountains), and the advancing Hubbard Glacier, the continent’s biggest tidewater glacier with a towering ice face that regularly calves massive icebergs into the sea. While smaller glaciers exist in the contiguous U.S.—such as Emmons Glacier on Mount Rainier, the largest in the lower 48 states—Alaska’s remote wilderness holds the true titans, many of which are retreating or surging in response to warming temperatures. These icy wonders attract scientists, adventurers, and tourists seeking to witness one of Earth’s most powerful natural forces in action.
1) Bagley Icefield
The Bagley Icefield is widely regarded as the largest icefield in the United States, covering approximately 863 square miles in southeastern Alaska near Cordova. Stretching 127 miles long, up to 6–10 miles wide, and reaching thicknesses of 3,000 feet, this massive subpolar icefield dominates the core of the Saint Elias and Chugach Mountains. It feeds dozens of outlet glaciers, including those connected to the Bering Glacier system, and forms part of one of North America’s most extensive non-polar glacial complexes. Located within the remote wilderness of Wrangell-St. Elias National Park, the Bagley Icefield is a critical reservoir of freshwater and a focal point for scientific research on glacial dynamics and climate change.
2) Bering Glacier
Bering Glacier ranks as one of the largest glaciers in the United States (and often cited as North America’s largest when combined with the Bagley Icefield, totaling over 1,900 square miles), spanning about 624 square miles near Cordova in southeast Alaska. This dynamic surge-type glacier stretches more than 120 miles and is famous for periodic surges every 20 years or so, followed by retreats that have caused overall shrinkage since 1900. Terminating in Vitus Lake just miles from the Gulf of Alaska, it plays a key role in regional hydrology and has been linked to seismic activity as the ice adjusts the Earth’s crust. Its
dramatic calving and advancing terminus make it a prime subject for glaciologists studying climate impacts in Alaska.
3) Juneau Icefield
The Juneau Icefield is the third-largest glacier complex in the United States, encompassing roughly 563 square miles in the Coast Mountains just outside Juneau, Alaska. This vast icefield nourishes more than 40 outlet glaciers, including the world-famous Mendenhall Glacier, which is easily accessible by road and a top tourist destination. Spanning about 85 miles north to south, it receives heavy snowfall and serves as a major source of freshwater for the region while offering helicopter tours, hiking trails, and scientific monitoring stations. As one of the more visitor-friendly large icefields in Alaska, the Juneau Icefield highlights the rapid retreat affecting Southeast Alaska’s glaciers due to warming temperatures.
4) Harding Icefield
Harding Icefield ranks fourth among the largest glaciers in the United States with approximately 399 square miles (some sources cite up to 700 including outflows), crowning the Kenai Mountains within Kenai Fjords National Park on the Kenai Peninsula. Formed during the Pleistocene Epoch and fed by up to 60 feet of annual snowfall, it spawns numerous outlet glaciers such as Exit Glacier and Bear Glacier, many of which are accessible for hiking or boat tours. The icefield’s dramatic fjord-carved landscape draws thousands of visitors each year, making it one of Alaska’s premier destinations for experiencing active glaciation up close. Its ongoing melt contributes significantly to sea-level rise studies in the region.
5) Nabesna Glacier
Nabesna Glacier is one of the longest valley glaciers in North America, flowing about 53–80 miles from the Wrangell Mountains in Wrangell-St. Elias National Park, Alaska, and covering roughly 353 square miles. As the world’s longest interior valley glacier, it drains an extensive icefield on the northern flanks of Mount Wrangell and is visible from the scenic Nabesna Road, offering rare road-access views of a massive Alaskan glacier. The glacier has been retreating slowly for over a century, revealing ancient forests and moraines that tell the story of past ice ages. It remains a highlight for backcountry adventurers and researchers studying long-term glacial change in the interior.
6) Jefferies Glacier
Jefferies Glacier (sometimes spelled Jeffries) covers approximately 310 square miles in the rugged St. Elias Mountains of Wrangell-St. Elias National Park, Alaska. This substantial valley glacier flows from high peaks near Mount St. Elias and forms part of the park’s immense glacial network, which accounts for much of Alaska’s total ice coverage. Known for its remote and challenging terrain, it attracts mountaineering expeditions and scientific teams exploring the region’s extreme glaciated wilderness. Like many Alaskan glaciers, Jefferies is retreating due to climate warming, yet it continues to shape the dramatic mountain landscape around it.
7) Wrangell Icefield
The Wrangell Icefield spans about 246 square miles amid the volcanically active Wrangell Mountains in Wrangell-St. Elias National Park, Alaska. This high-elevation icefield supports multiple glaciers and sits among some of North America’s tallest peaks, including Mount Wrangell, an active shield volcano. Its ice contributes to the park’s extraordinary glacial coverage and creates stunning contrasts with surrounding lava flows and rugged terrain. Though remote and best viewed via flightseeing tours, the Wrangell Icefield offers valuable insights into how volcanic activity and glaciation interact in one of the most dynamic landscapes in the United States.
8) Martin River Glacier
Martin River Glacier is a notable 25-mile-long glacier in the Yakutat-Copper River region of Alaska’s Chugach Mountains, covering a significant area within the coastal glacial complex. Flowing southwest from tributaries linked to the Bagley Icefield, it terminates at the head of the Martin River and features classic glacial landforms, including moraines and debris-covered zones that reveal centuries of advance and retreat. Researchers have documented its history through the Little Ice Age and ongoing thinning, making it an important site for studying glacial geology and landscape evolution in southern Alaska. Its remote location limits casual visits but rewards scientific and adventurous exploration.
9) Hubbard Glacier
Hubbard Glacier is North America’s largest tidewater glacier, stretching 76 miles long with a 7-mile-wide face that towers up to 400 feet high where it calves into Disenchantment Bay near Yakutat, Alaska. Located in Wrangell-St. Elias National Park, it is one of the few advancing glaciers in the region and is renowned for dramatic iceberg calving that can temporarily dam Russell Fjord. Cruise ships regularly visit its massive ice cliffs, making it one of Alaska’s most accessible and spectacular glaciers for tourists. Its ongoing activity provides a vivid example of how tidewater glaciers respond to climate and ocean influences.
10) Black Rapids Glacier
Black Rapids Glacier, a classic surge-type glacier in the Alaska Range near Delta Junction, covers approximately 197 square miles and stretches about 25–30 miles along the Richardson Highway. Nicknamed the “Galloping Glacier” after its famous 1936–1937 surge that advanced several miles in months (threatening the highway), it is one of the most studied surge glaciers in the world. Located close to a major fault line, it offers scientists a natural laboratory for understanding rapid ice flow and seismic-glacial interactions. Though currently in a quiescent phase, Black Rapids remains a striking sight for highway travelers and highlights the dynamic nature of Alaska’s interior glaciers.
These paragraphs are optimized for search visibility while remaining factual and engaging. All rankings and sizes draw from consistent recent datasets, though exact measurements can vary slightly wit