Wao is a second class municipality in the province of Lanao del Sur, Philippines. According to the 2015 census, it has a population of 45,862 people. It is the only municipality in the Philippines that begins with W. Wao is also surrounded by Bumbaran in the north and west, Bukidnon in the east, and Cotabato to the south. ^ Census of Population. "ARMM - Autonomous Region in Muslim Mindanao". Total Population by Province, City, Municipality and Barangay. PSA. Retrieved 20 June 2016.