how deep is the earth's crust

The Earth's crust varies in thickness depending on whether it is continental or oceanic crust. The continental crust is generally thicker, averaging between 35 and 40 kilometers (about 22 to 25 miles), with some regions such as young mountain chains like the Himalayas reaching up to about 70 kilometers (43 miles) in thickness. In contrast, the oceanic crust is much thinner, averaging about 7 kilometers (around 4.3 miles) thick. The crust is the outermost layer of the Earth, and beneath it lies the mantle. The thinnest oceanic crust can be about 5 kilometers (3 miles) thick, while continental crust can range from approximately 20 to 70 kilometers thick depending on geological factors. Overall, the Earth's crust is very thin relative to the total radius of the Earth, which is over 6,300 kilometers.