Local Group :
The Local Group is a group of more than 20 galaxies to which the Milky Way Galaxy belongs. About half are elliptical galaxies, with the remainder being of the spiral or irregular type. As in other clusters of galaxies, members are probably kept from separating by their mutual gravitational attraction. The Milky Way system is near one end of the volume of space occupied by the Local Group, and the great Andromeda galaxy (M31) is near the other end, about 2,000,000 light-years away.
Excerpt from the Encyclopedia Britannica without permission.