Just How Big Is The Star Wars Galaxy?

For something called the 'Unknown Regions', quite a lot is known about what exists there.

The Unknown Regions holds quite a few planets which have been explored over the Star Wars story. The 2003 game, Star Wars: Knights of the Old Republic, introduced Rakata Prime, homeworld of the Rakata. The Rakata built the dreaded Star Forge, a station capable of churning out huge armies immensely quickly, and were thought to be the inventors of hyperspace travel. The region also contained the planets Ahch-To and Csilla; Ahch-To being where Luke Skywalker was hiding after his failure to prevent Ben Solo from turning to the dark side, and Csilla is the home planet of the Chiss species, of which imperial villain, Grand Admiral Thrawn, is a member of.

Another world that lies in the Unknown Regions is the Sith planet, Exegol. This is where Palpatine transported his consciousness to a clone body through the Sith ability, essence transfer, after Anakin Skywalker was redeemed and betrayed his master on the second Death Star. The world held the Sith Eternal cultists, who wanted to retake the galaxy for Palpatine, seen in Star Wars: The Rise Of Skywalker.

The Unknown Regions were also where remnants of the Empire fled to after their defeat at the Battle of Endor, and they would return decades later as the First Order.