Greenland’s major physical feature is its massive ice sheet, which is second only to Antarctica’s in size. The Greenland Ice Sheet has an average thickness of 5,000 feet (1,500 metres), reaches a maximum thickness of about 10,000 feet (3,000 metres), and covers more than 700,000 square miles (1,800,000 square km)—over four-fifths of Greenland’s total land area.