The largest galaxy in our local group is the Andromeda Galaxy, also known as M31. It is a spiral galaxy located about 2.537 million light-years from Earth and is expected to collide with the Milky Way in approximately 4.5 billion years. Andromeda is approximately 220,000 light-years in diameter, making it about twice the size of the Milky Way. It has a significant number of stars, estimated to be around one trillion, and is home to various star clusters and nebulae. As one of the nearest major galaxies, Andromeda has been a focal point for astronomical observation and study.