The galaxies in our universe are typically found in clusters with other galaxies. Our ‘Local Group’ consists of about 50 galaxies and is about 50 million light years across. There are only three spiral galaxies in our group. The Andromeda galaxy at 200,000 light years across is slightly larger than the Milky Way. The third spiral galaxy is called the Triangulum Galaxy and is about half the size of the Milky Way. The other galaxies in our Local Group are small irregulars and dwarf elliptical galaxies.
(The Great Courses – A Visual Guide to the Universe)