Ennis Outpost was a Federation research outpost established in 2370 to research the planetary ring system around the planet Heaven, and was built on Heaven's most stable moon, Ennis. The outpost's first director was Jarod Maher.
During the USS Enterprise-D's visit to the outpost in early 2371, it was very much in its infancy, with packing crates lining every corridor and exposed power conduits all over the outpost. Additionally, the outpost's shuttlebay was only equipped with an aging shuttlecraft. (TNG - The Sky's the Limit short story: "'Twould Ring the Bells of Heaven")