The Last Glacial Maximum (LGM) refers to the time of maximum extent of the ice sheets during the last glacial period, between twenty-six thousand five hundred and nineteen thousand to twenty thousand years ago.

The Younger Dryas will follow the Last Glacial Maximum.

Ice sheets cover the whole of Iceland and all but the southern extremity of the British Isles.

This ice extends northward to cover Svalbard and Franz Josef Land and eastward to occupy the northern half of the West Siberian Plain, ending at the Taymyr Peninsula, and damming the Ob and Yenisei rivers forming a West Siberian Glacial Lake.

Northern Europe is largely covered, the southern boundary passing through Germany and Poland, but not quite joined to the British ice sheet.

Permafrost covers Europe south of the ice sheet down to present-day Szeged and Asia down to Beijing.

The ice covers essentially all of Canada and extends roughly to the Missouri and Ohio Rivers, and eastward to New York City.

Alpine glaciers advance in addition to the large Cordilleran Ice Sheet in Canada and Montana, covering much of the Rocky Mountains in the United States.

Latitudinal gradients in North America are so sharp that permafrost does not reach far south of the ice sheets except at high elevations.

Ice sheets also cover Tibet (scientists continue to debate the extent to which the Tibetan Plateau was covered with ice), Baltistan, Ladakh, the Venezuelan Andes, and the Andean altiplano.

The Patagonian Ice Sheet covers Chile and western Argentina north to roughly forty-one degrees south.