The Wraith Domain is a polity composed of dozens of individual sovereign Wraith hives that rules over various territories in half of the Pegasus galaxy.
It once formally controlled much of Pegasus until 2009, when the Wraith ceded half the galaxy to its large human population.
History
During the war with the Ancients, the Wraith captured many worlds in Pegasus with its large populations to use as feeding grounds. They also control some uninhabited planets which they use as outposts, construction sites, and research bases.
In 2005, the Wraith's control over Pegasus was challenged after 10,000 years when humans from Earth discovered Atlantis and began to fight against them after accidentally awakening them into a galaxy where the population numbers have yet to reach a level where the Wraith could feed causing a number of incidents. It was in this time that several planets formed an alliance with others creating a united government while the Wraith warred against each other. A number of the Wraith's all important and seat of government, known as Hive ships were destroyed drastically reducing their fighting capability until a Wraith Queen known as Death took control of the Wraith and began a drive to get her people to Earth.
In the aftermath of Death's defeat and subsequent death, the remaining Wraith forged a peace agreement and, as such, half of the Pegasus galaxy controlled by the Wraith was given to the Tau'ri. (SGA: "The Lost", "Legacy")
Politics
Well, for one, they seem to be territorial. Very much so, it turns out. They're not a united foe like we once believed.Jace
The Wraith Domain is a unusually decentralized polity, due to the Wraith possessing an extremely strong territorial instinct, making inter-Wraith cooperation a rare event and is instead a confederal entity divided into dozens of individual sovereign hives. (SGA: "Rising", "The Lost Boys")
Hive queens hold a great deal of power within each hive and are at the top of their hierarchy, with day to day duties running dealt with by Wraith Commanders. (SGA: "Spoils of War", "The Queen")