The Pegasus Galaxy is a galaxy in the Stargate universe. It is notable for being colonized by the Ancients and being the home of Atlantis and the Wraith. It is 3,000,000 light years away from the Milky Way.
Even though it is not stated, the Pegasus Galaxy is presumed to be the Pegasus Dwarf Irregular Galaxy.
The Pegasus Galaxy was first colonized by a group of Ancients after abandoning the Earth, seeding human civilizations across it and letting them develop on their own paths.