The Betreka Nebula was an interstellar gas cloud located adjacent to the Klingon Empire and the Cardassian Union. The nebula was the site of the Betreka Nebula Incident between the two powers. (DS9: "The Way of the Warrior") This nebula was only mentioned in dialogue. According to Star Trek: Star Charts (p. 47) and Stellar Cartography: The Starfleet Reference Library ("Federation Historical Highlights, 2161-2385"), this nebula was located in the Alpha Quadrant.