The Great Andromeda Galaxy. The Great Andromeda Galaxy (M31; NGC 224) is located 2.2 million light years from Earth in the constellation Andromeda. At 200 light years across it is the largest galaxy in the "local group" - the cluster of around 25 galaxies that includes our own, the Milky Way. Like the Milky Way, Andromeda is a spiral galaxy with a dense central bulge packed with millions of stars.