What is the name of the largest ice sheet on Earth?

The Antarctic Ice Sheet is the largest ice sheet on Earth. It is a continental glacier covering about 98% of Antarctica, with an area of roughly 14 million square kilometres.

The ice sheet contains approximately 26.5 million cubic kilometres of ice—around 61% of all the fresh water on Earth. Its ice averages more than 2 kilometres thick, although thickness varies greatly across the continent. The Transantarctic Mountains divide it into the much larger East Antarctic Ice Sheet and the smaller West Antarctic Ice Sheet; the Antarctic Peninsula is sometimes discussed separately because of its distinct ice-flow systems.

This answer is commonly confused with the Greenland Ice Sheet, the other major ice sheet still present today. Greenland is enormous, but Antarctica’s ice sheet is larger in both area and volume. Individual glaciers such as Thwaites Glacier are important outlets within the Antarctic system, but they are not themselves ice sheets. Ice shelves that float beyond the coastline are also different from the grounded continental ice sheet, even though they are connected to it.