The Pallas 14 system was a planetary system. This was a binary star system with three planets. The second planet, Mantilles, was suitable for colonization by humanoid life-forms. Prior to 2269, the Federation would establish a colony on this planet. The outermost planet was Alondra. The system was located at the outer fringe of the Milky Way Galaxy (TAS: "One of Our Planets Is Missing") Pallas 14 was located in the Alpha Quadrant. Its location was depicted on a Federation star chart in 2293. (Star Trek VI: The Undiscovered Country, production art)
In 2269, Mantilles, one of the inner planets in the system, was the most remote inhabited planet of the Federation. The planet's governor was Robert Wesley, a retired Starfleet commodore. Mantilles had a population of 82 million.
During that year, the system was invaded by a huge cosmic cloud creature, which began to consume the system. After consuming Alondra, the cloud creature threatened to engulf Mantilles. It was convinced by the crew of the USS Enterprise to leave the galaxy. (TAS: "One of Our Planets Is Missing")