The Devron system is a star system within the Romulan Neutral Zone.
The Devron system was the origin of an anti-time temporal anomaly created by Captain Jean-Luc Picard in 2395 which was nearly responsible for the destruction of the Human race billions of years ago. The anomaly was unknowingly created by Picard while playing one of his many games with Q. (TNG: "All Good Things...")