Trefolg was one of the Federation's closest colonies to the Neutral Zone. It was equipped with high-powered subspace radio equipment to account for its distance from Federation support. Trefolg's governor in 2269 was Lerak Kepac, around which time the colony was suffering from a deficiency in refined, alloyed metal.
Also in 2269, members of the United Expansionist Party acquired a starship on Trefolg and planned an incursion into the Neutral Zone to spark a conflict between the United Federation of Planets and the Romulan Star Empire. The conspirators were captured by colonial authorities and transferred to Starfleet custody aboard the USS Enterprise. (TOS novel: The Trellisane Confrontation)