Terok Nor, the Cardassian space station in orbit of Bajor, was abandoned when the Cardassian occupation ended. This left the Bajorans in control of the station and they assumed ownership of it. Shortly thereafter the Bajorans petitioned for entry into the Federation and requested assistance in repairing and running the station, but it was still Bajoran property. source: Deep Space 9 and the Federation
I am curious, however, on why the station was named Deep Space Nine, instead of being given a Bajoran name. Was this simply to try and please the Federation, in an attempt to move along their entry application, or was it a requirement of the Federation, that they get to name the station if they are going to manage it? Or was there some other reason given?