

(formerly known as Terok Nor) is situated in the Bajoran Solar System and regulates traffic to and from the Gamma Quadrant.
The space station was built during the Cardassian occupation in 2351, to regulate the strip mining of the planet Bajor.
When the Cardassians withdrew from Bajoran Space in 2369, they also abandoned the station but not before both wrecking it and concealing booby traps.
Starfleet were asked to assist by the Bajoran Provisional Government and took command of Deep Space Nine, Benjamin Sisko was placed in charge of the station.
Deep Space Nine assumed great commercial, scientific, and strategic importance when the Bajoran Wormhole was discovered soon after Star Fleet arrived. The wormhole links the Bajoran system with the distant Gamma Quadrant.
This information was put together from facts gathered from various sites if you know of a good DS9 link please e-mail me and I will add it below.