Eighty-five percent of its 2,175,600 sq km area is covered with a massive ice cap that reaches 3,200 m near the center and is over 1,370 m thick in places. Only the Antarctic ice sheet is larger.
Annual snows accumulate on the cap and due to weight, the ice flows out toward the edges.
From the central mass, ribbons of ice descend along mountain valleys and ravines, pushing hills or large rocks and gravel before them. At other times, the glacier may crown or appear to hang atop high cliff faces. The glacier directly joins the sea in some locations and may move at rates up to 25-30 m each day, berthing icebergs the size of city blocks. Northwest Greenland is known as the Thule District or Avanersuaq. Greenland was under European colonial rule since 1721.