The Tarranian settlement was a planet in the Pegasus galaxy which became the new homeworld of the Taranians after their first homeworld, Taranis was rendered uninhabitable after the supervolcanic eruption.
Before the planet was visited by the Atlantis expedition, the world was inhabited by a race of people who had the same capabilities as the Genii and also built a network of underground tunnels to hide from the Wraith. What happened to this people remains unknown, although their underground bunkers survived.
After evacuation the Taranians, there were eventually settled on this planet and helped to rebuild their civilization. Unfortunately, the planet was chosen by Michael Kenmore as the place to breed a new army of soldiers using the Iratus bug. He hid in the underground tunnels and kidnapped all the Taranians to use them for his experiments, eventually killing all of them. After several weeks, Lt. Colonel John Sheppard's team visited the planet to find out what had happened to the Taranians, which resulted in a battle between them and Michael's Bug People. Michael eventually fled the planet with his creatures. (SGA: "Vengeance")