The following is a list of mentioned planets and star systems in the Romulan Star Empire. All planets listed are or were inhabited at some point of time.
Planets
- Benzar (Federation planet liberated from the Dominion by Romulan forces in 2374)
- Carraya IV (Carraya system) (likely outside of actual Romulan territory)
- Chaltok IV
- "Eden" (likely uninhabited)
- Khitomer (Khitomer system, site of a Klingon colony at least until 2346, within Romulan territory as of 2369)
- Rator III
- Remus (Romulan system)
- Romulus (Romulan system)
- Unnamed Romulan planet near Neutral Zone
- Unnamed Minshara-class planet
The reference book Star Trek: Federation - The First 150 Years identifies the Romulan planet shown in ENT: "Minefield" as Unroth III.
Since the expansion of the Romulan Star Empire is most likely based upon conquest and not the peaceful admission of single planets, it is possible that, if one planet is Romulan, the whole system may be seized by the Star Empire, too.
Stars, star systems and other stellar phenomena
- Bassen Rift
- Beta Hutzel
- Nequencia Alpha system (likely outside of actual Romulan territory)
- Romii
- Tomed (uncertain)
- Unroth system
- Galorndon Core
Tranome Sar was mentioned as the site of a battle between the Klingons and the Romulans, therefore it might be a planet or star within the Romulan Star Empire.