The baselines of the Philippines (Filipino: mga batayang-guhit ng Pilipinas) are the set of geodesic lines completely encircling the Philippine archipelago from where the maritime entitlements of the country are measured. It was first established in 1961[1] by an act of the Congress of the Philippines which was further amended in April 2009 to optimize and conform it to the United Nations Convention on the Law of the Sea, to which the Philippines is a signatory. A total of 101 basepoints providing for 100 baselines were identified under Republic Act No. 9522, which identified Amianan Island as the northernmost, Frances Reef as the southernmost, Pusan Point as its easternmost and the Balabac Great Reef as the westernmost points of the main Philippine archipelago.[2]