The inner ring of Deep Space 9, lying between the central core and the docking ring, which holds the crew and guest quarters and the landing pads for the station's runabouts.
The habitat ring is where most of Deep Space 9's population lives. Its corridors lead to the quarters of the Sisko and O'Brien families, of Kira, Dax, Bashir and Worf, and to the guest quarters given to visiting ambassadors and to rather less welcome arrivals.
Built into the ring's upper surface are the runabout pads, from which craft such as the Rio Grande are raised on lifts before launch. Odo, who needs no bed, eventually furnishes quarters there with shapes to practise on, as seen in The Abandoned.
The quarters are Cardassian in design, and the crew spend years softening them with their own belongings. Much of The Assignment, in which Keiko O'Brien is possessed by a Pah-wraith, unfolds in the O'Brien family's quarters there.