Basilan Island
The Philippine tarsier, as its name suggests, is endemic to the Philippine archipelago. "C. syrichta" populations are generally found in the southeastern part of the archipelago. Established populations are present primarily on the islands of Bohol, Samar, Leyte and Mindanao. It has also been found on various isolated islands within its known range, such as Maripipi Island, Siargao Island, Basilan Island and Dinagat Island.