Epsilon Indi was the primary of the inhabited Epsilon Indi system. This system of the Alpha Quadrant was located less than 20 light years from Sol. (TOS: "And the Children Shall Lead", TNG: "The Naked Now", "Datalore", "Conspiracy")
In early history, a band of marauders based around Triacus wreaked chaos on the inhabitants of the Epsilon Indi system. After many centuries of intrusion, the inhabitants of Epsilon Indi were finally able to rise up and destroy the marauders, leading to their corporeal extinction. (TOS: "And the Children Shall Lead")
On several occasions in 2364, viewscreen readouts aboard the USS Enterprise-D showed the location of Epsilon Indi, in the form of charts from the Enterprise library computer. (TNG: "The Naked Now", "The Last Outpost", "Conspiracy")
The star chart naming stars within 20 light years of Sol was drawn by Rick Sternbach for the Star Trek Spaceflight Chronology in the late 1970s. Found on page 77, this chart showed Earth commercial and exploration routes after the use of warp drive began. There were no commercial or exploration routes to Epsilon Indi. The stars Alpha Centauri, Sol, Sirius, and Tau Ceti were identified on "The Explored Galaxy" wall chart as being located in the Alpha Quadrant.
According to the Star Fleet Technical Manual, the Star Empire of Epsilon Indii was one of the founding members of the Federation. The eighth planet of the Epsilon Indi was stated to be Andor, the homeworld of the Andorian race in The Worlds of the Federation.
Epsilon Indi (Draylax) was located in the Beta Quadrant. One of the planets in this system was named Draylax. In the mid-22nd century, this system was named as a stop on the Earth trade routes. Epsilon Indi was classified as a K class star. It had a magnitude of +7, which was 1/10 as bright as Sol.