The Nelvana system was a planetary system. This system had five planets that orbited the primary Sigma Nelvana. During the mid-24th century, the uninhabited system was a strategically significant point in the Romulan Neutral Zone.

In 2366, the Romulans deceived the Federation into believing they had established a secret base on Nelvana III, and successfully lured the USS Enterprise-D there to respond. (TNG: "The Defector")