A lawless Earth colony where the government collapsed and rival gangs fought for control, the world where Tasha Yar grew up.
Turkana IV is a former Earth colony whose government broke down, leaving its population caught between armed factions. Tasha Yar was born there and survived a brutal childhood on its streets before escaping to join Starfleet. By the time of the Enterprise visit only two main factions, the Coalition and the Alliance, remain, and residents are fitted with implanted proximity detectors to mark their allegiance.
In Legacy, the Enterprise comes to Turkana IV to rescue the crew of the freighter Arcos after their escape pod lands there. The mission brings Data and the crew into contact with Tasha's sister Ishara, who still lives and fights on the planet.