How thick is the crust of the earth? July 19, 2020 by Pamela Landy Sometimes likened to the shell that covers an egg, the layer of rock or crust that covers the surface of the earth is, on average, 22 miles thick. Related Answers What causes hail? How many continents are there? What is the deepest circle of Hell in Dante’s Inferno? How thick is the ice that covers Antarctica? How much of the earth’s surface is permanently frozen? How much of the earth is unexplored?