The Phelan system was an inhabited star system. This system was located 53 hours from the planet J'naii at warp factor 6.

In 2368, Starfleet Command sent a request to the USS EnterpriseD asking if the ship could proceed with its mission in the Phelan system. The ship's crew would negotiate a trade agreement with the inhabitants of that system. Upon completion of the mission at J'naii, the Enterprise traveled at warp factor 6 to the Phelan system. (TNG: "The Outcast")

According to the Star Trek Encyclopedia (4th ed., vol. 2, p. 138), the Phelan system was located some 2.8 light years from J'naii.