Half Dome is a quartz monzonite batholith at the eastern end of Yosemite Valley in Yosemite National Park, California.
It is a well-known rock formation in the park, named for its distinct shape. One side is a sheer face while the other three sides are smooth and round, making it appear like a dome cut in half.

Standing at nearly 2.7 Kilometres (8,800 feet) above sea level, it’s composed of quartz monzonite, an igneous rock that solidified several thousand feet within the Earth.
At its core are the remains of a magma chamber that cooled slowly and crystallized beneath the Earth’s surface. The solidified magma chamber was then exposed and cut in half by erosion, therefore leading to the geographic name Half Dome.