Ice sheet is a very large, thick layer of ice that covers a wide area of land. It can be several kilometers thick and spread across large regions. Ice sheets are made from layers of snow that have built up and compressed over time. They move slowly across the land beneath them.

Ice sheets are mainly found in Antarctica and Greenland. They formed over many thousands of years during long periods of cold climate. Ice sheets contain most of Earth’s freshwater ice. They are an important part of polar environments.