|Affiliation:||United Federation of Planets (protectorate)|
Turkana IV was the fourth planet of the Turkana planetary system. This system was located in the Alpha Quadrant. The planet was suitable for colonization by humanoid life-forms. Sometime prior to the 2330s, an Earth colony was established on this planet. Its main settlement was Turkana City.
The planet's government began breaking down in the 2330s. Dozens of factions developed, and civil war broke out. The Turkana government gave emergency powers to the two largest factions, the Coalition and the Alliance, but it was quickly overthrown by those cadres, and the planet broke away from the Federation in the 2350s, the two factions declaring the planet's independence. Lawlessness became the norm, and rape gangs became a common threat. Few citizens escaped the planet. One of those fortunate enough to do so was Tasha Yar, who left the planet at age fifteen, and later went on to become a Starfleet officer. (TNG: "The Naked Now")
Six years later, the USS Enterprise-D visited Turkana IV, in response to a distress call from the freighter Arcos. The Arcos was lost, but survivors crash-landed on the planet in an escape pod. At that time, the surface structures had all been destroyed by years of civil war, and the planet's inhabitants lived in structures that extended up to three kilometers below the surface. Proximity detectors were used to separate the two factions, and both sides' bases were heavily defended, in order to prevent all-out conflict. (TNG: "Legacy")