The Andromeda Galaxy is currently made accessible from a wormhole located centrally to many different galactic powers from the Milky Way Galaxy. This will contain any and all information currently known about the Andromeda Galaxy.
Currently, this is what is known about the Andromeda Galaxy
Terrannia - 3 planets, 1 M Class. Former Federation Colony
United Federation of Planets - Currently controls both sides of the wormhole. Attempting to regain foothold in nearby Terrannia System.
The list of all known races in the Andromeda Galaxy can be found here.
200 years ago, the wormhole opened, linking the Milky Way and Andromeda Galaxies. Every race and galactic empire scrambled for the new territory, but then the wormhole suddenly disappeared. It reappeared 200 years later in the same place on both ends. As of now, no other civilization has been contacted on the Andromeda side of the galaxy. Starbase Dragonstar sits between the wormhole and Terrannia.