The Zenas Expanse is a region of space that encompasses borders of the United Federation of Planets and the Romulan Star Empire, as well as an expanse extending from these borders deeper into the galaxy's Alpha Quadrant. This region was accessible from the Arawath sector and the Vanden sector of the Zeta Andromedae sector block. The Zenas Expanse was made up of a good deal of space not yet explored by the Cardassians as of the 25th century. (STO video game: Star Trek Online; STO mission: "Explore the Zenas Expanse")