The Unidentified Nations of the galaxy are space-faring nations that are known to have existed via historical records, or theorized to exist due to extenuating circumstances, but their names, cultures, peoples, and all other relevant data are unknown. This does not include the residents of the Angel Sector, who are unknown but identified.
- A human nation attempted to colonize Akanda during the Izeran Stone Age before disappearing. One explanation for this is that all records of a colonization fleet were lost by their nation during the Dark Age. Due to the presence of humans without ties to any known nation, the possibility of a second unidentified galactic power uplifting a select group of humans remains a possibility. Another possibility is that they were a humanoid nation unrelated to the human nations descended from Earthlings.
- Ancient illustrations found within tunnels in Ras Orkto support the hypothesis that the Rakasha once practiced slavery of both their own race and others, though these other races are unknown.
- Shortly after the Plague of the Prideful reduced the Rrakashian and Rakashian populations by 90%, a humanoid species that potentially came from outside the Ras solar system claimed Ras Utiku as their own, killing off the remaining Rrakashians.
- In 2667, a probe from an unknown power crashed onto the Ashkathi homeworld of Larine in an event known as the Day of Ascension. There are theories that this probe is Norb in origin, though studies do not support this.
- In 2721, the Sirians were uplifted and subjugated by an unidentified alien race that granted them technology such as superluminal drives, and used them in a galactic war.