Castor

Castor
Astrographical
Total stars	327 billion
Star systems	113 billion
Size	101,250 light years (longest axis)
Globular clusters	135
Societal
Regions	The Coreworlds Expansion Region The Colonies The Hithi Arm The Outer Rim Wild Space Gold Rush Region
Sentient species	10 million+

[Source]

Castor is one of the two galaxies that make up The Twins. Castor is an average barred spiral galaxy and the home of Humans.