During the last ice age, which occurred about 20,000 years ago, ice sheets covered large parts of the Earth's surface. The most extensive ice sheets were located in North America, Europe, and Antarctica.

In North America, the Laurentide Ice Sheet covered most of Canada and the northern United States. It extended as far south as the present-day Ohio River Valley.

In Europe, the Fennoscandian Ice Sheet covered most of Scandinavia and the Baltic Sea region. It extended as far south as present-day Germany.

In Antarctica, the Antarctic Ice Sheet covered the entire continent. It was much thicker than it is today, and it extended over much of the surrounding ocean.

In addition to these major ice sheets, there were also smaller ice sheets in Greenland, Iceland, the Arctic islands, and the Andes Mountains of South America.