The Beta Quadrant was the common designation for one-quarter of the Milky Way Galaxy. It was adjacent to the Alpha and Delta Quadrants. One-quarter of the galactic core was located in this quadrant.
Qo'noS, the Klingon homeworld, was located in the Beta Quadrant. The Klingon Empire and the Romulan Star Empire claimed territory in the Beta Quadrant in the 24th century.
The Yattho, a species known for their precognitive abilities, were native to the Beta Quadrant.