Topography

Zamboanga del Sur is occupying the southern section of the Zamboanga Peninsula that forms the western part of the island of Mindanao. It is located within longitude 1220 54' to 1230 40' east and latitude 70 22' to 80 20' north. It is bounded in the north by the Province of Zamboanga del Norte, in the south by the Moro Gulf, in the southwest by the newly-created Province of Zamboanga Sibugay, in the east by the Province of Misamis Occidental, the Panguil Bay and a portion of Lanao del Sur Province.

Stretching northward from Sibugay Province in the southwest and running along the northern boundary onward to Salug Valley in the east is a mountainous country. The coastal plains are narrow strips extending regularly from the southwest, then spreading into wide flat lands when reaching the coastal plains of Baganian Peninsula in the southeast.