Alpha Quadrant emblem.
The colloquially named Alpha Quadrant frontier zone was an area of space within the Milky Way Galaxy's Alpha Quadrant. It was situated on the edge of the United Federation of Planets, proximate to the Tholian Assembly and some smaller galactic powers. Casroc, homeworld of the Dinac was located between the zone and planet Earth.
In the year 2386, Fleet Admiral Leonard James Akaar appointed Rear Admiral William T. Riker as acting sector commander of the zone. The starship Titan served as his mobile base of operations. (TTN novel: Sight Unseen)