Pine Island Glacier in the context of "Iceberg"

The Antarctic ice sheet is a continental glacier covering 98% of the Antarctic continent, with an area of 14 million square kilometres (5.4 million square miles) and an average thickness of over 2 kilometres (1.2 mi). It is the largest of Earth's two current ice sheets, containing 26.5 million cubic kilometres (6,400,000 cubic miles) of ice, which is equivalent to 61% of all fresh water on Earth. Its surface is nearly continuous, and the only ice-free areas on the continent are the dry valleys, nunataks of the Antarctic mountain ranges, and sparse coastal bedrock. It is often subdivided into the Antarctic Peninsula (AP), the East Antarctic Ice Sheet (EAIS), and the West Antarctic Ice Sheet (WAIS), due to the large differences in glacier mass balance, ice flow, and topography between the three regions.

Because the East Antarctic Ice Sheet is over 10 times larger than the West Antarctic Ice Sheet and located at a higher elevation, it is less vulnerable to climate change than the WAIS. In the 20th century, EAIS had been one of the only places on Earth which displayed limited cooling instead of warming, even as the WAIS warmed by over 0.1 °C/decade from 1950s to 2000, with an average warming trend of >0.05 °C/decade since 1957 across the whole continent. As of early 2020s, there is still net mass gain over the EAIS (due to increased precipitation freezing on top of the ice sheet), yet the ice loss from the WAIS glaciers such as Thwaites and Pine Island Glacier is far greater.

Thwaites Glacier is an unusually broad and vast Antarctic glacier located east of Mount Murphy, on the Walgreen Coast of Marie Byrd Land. It was initially sighted by polar researchers in 1940, mapped in 1959–1966 and officially named in 1967, after the late American glaciologist Fredrik T. Thwaites. The glacier flows into Pine Island Bay, part of the Amundsen Sea, at surface speeds which exceed 2 kilometres (1.2 mi) per year near its grounding line. Its fastest-flowing grounded ice is centered between 50 and 100 kilometres (31 and 62 mi) east of Mount Murphy. Like many other parts of the cryosphere, it has been adversely affected by climate change, and provides one of the more notable examples of the retreat of glaciers since 1850.

Thwaites Glacier is closely monitored for its potential to elevate sea levels. Since the 1980s, Thwaites and Pine Island Glacier have been described as part of the "weak underbelly" of the West Antarctic Ice Sheet, in part because they seem vulnerable to irreversible retreat and collapse even under relatively little warming, but mainly because if they go, the entire ice sheet is likely to eventually follow. This hypothesis is based on both theoretical studies of the stability of marine ice sheets and observations of large changes on these two glaciers. In recent years, the flow of both of these glaciers has accelerated, their surfaces have lowered, and their grounding lines have retreated. They are believed very likely to eventually collapse even without any further warming. The outsized danger Thwaites poses has led to some reporters nicknaming it the Doomsday Glacier, although this nickname is controversial among scientists.

There are many glaciers in the Antarctic. This set of lists does not include ice sheets, ice caps or ice fields, such as the Antarctic ice sheet, but includes glacial features that are defined by their flow, rather than general bodies of ice. The lists include outlet glaciers, valley glaciers, cirque glaciers, tidewater glaciers and ice streams. Ice streams are a type of glacier and many of them have "glacier" in their name, e.g. Pine Island Glacier. Ice shelves are listed separately in the List of Antarctic ice shelves. For the purposes of these lists, the Antarctic is defined as any latitude further south than 60° (the continental limit according to the Antarctic Treaty System).

The Hudson Mountains are a mountain range in western Ellsworth Land just east of Pine Island Bay at the Walgreen Coast of the Amundsen Sea. They are of volcanic origin, consisting of low scattered mountains and nunataks that protrude through the West Antarctic Ice Sheet. The Hudson Mountains are bounded on the north by Cosgrove Ice Shelf and on the south by Pine Island Glacier. The mountains were volcanically active during the Miocene and Pliocene, but there is evidence for an eruption about two millennia ago and uncertain indications of activity in the 20th century.

Iceberg B-46 is a large iceberg that broke free from Pine Island Glacier in Antarctica in October 2018. It was 225 km at its greatest extent. The iceberg was detected by the Landsat 8 satellite and later photographed by a NASA DC-8 as part of their IceBridge recording project.

The shedding of icebergs by the Pine Island Glacier used to occur on average every 6 years; but has become a near annual event.