Zamboanga del Sur occupies the southern and central portion of the Zamboanga Peninsula — the long arm of Mindanao extending westward into the Sulu Sea. Its capital, Pagadian City, sits on Illana Bay and is the regional center of the Zamboanga Peninsula. The original inhabitants of the peninsula were the Subanen along the inland rivers and the Sama-Bajau and Yakan on the coasts.
Pagadian is built on steeply rolling terrain above its sheltered bay. Its best-known symbol is a tricycle designed for the hills, with the cab tilted at about 25 to 40 degrees; it is said to be the only inclined public transport vehicle in the country. In recent years many have been replaced by quieter, more fuel-efficient "bao-bao" auto rickshaws.
Pagadian's hilly streets gave rise to its famous tricycle, designed for the city's terrain, with its cab inclined at about 25 to 40 degrees. The modern city grew from the sitio of Talapukan, a name meaning "a place where springs abound".
The 2024 census counted 2,063,975 people in Zamboanga del Sur, including Zamboanga City, a highly urbanized city that is grouped with the province for statistics but governed independently. The province has 26 municipalities and one component city, Pagadian. Cebuano is the most common first language, and Chavacano is the majority language in and around Zamboanga City.







