A prefect was the title for an administrating individual, who could be placed in a supervisory position over a base, labor camp or a planet.
Jaris was the prefect of Argelius II in 2267. (TOS: "Wolf in the Fold")
Dukat was the Cardassian prefect of Bajor for a period during the occupation of that world. (DS9: "Emissary")
As prefect, Dukat kept personal files about Kira Nerys, which were decrypted by Jadzia Dax and Miles O'Brien in 2369. (DS9: "Battle Lines")
While participating in a ruse to gain access to the Hutet labor camp on Cardassia IV in 2370, Miles O'Brien claimed that Kira had an appointment with the resident prefect. (DS9: "The Homecoming")
A Vidiian base on Avery III was also administrated by a prefect in 2371. When Peter Durst was separated from other prisoners, a guard stated that the prefect wanted to discuss the request to contact the USS Voyager, but in reality Durst would be killed. (VOY: "Faces")