From Wikipedia Edit
The nation of Kul'Tiras, located off the coast of Khaz Modan, and led by the Proudmoore family, has been a staunch ally of the Alliance since its foundation. Admiral Proudmoore, leader of Kul'Tiras, led the Alliance fleets during the Second War with great success and used Kul'Tiras as a major supply base against the Orcs. During the Third War, Kul'Tiras remained untouched by the plague and the strife occurring in Lordaeron, but it did supply many colonists and soldiers for the Alliance expedition to Kalimdor.
During the aftermath of the Third War, Admiral Daelin Proudmoore set sail from the island into the Great Sea seeking his daughter, Jaina Proudmoore. Upon reaching the shores of Kalimdor, the Kul'Tiras navy immediately attacked the Orcish Horde, not knowing of the alliance that had overthrown the Burning Legion. The attack was ultimately dismantled however and much of the Kul'Tiras navy was effectively destroyed with the death of Proudmoore. Kul'Tiras is currently inaccessible in World of Warcraft.
It is thought that this area will become accessible in a following patch or expansion.