Isulan, officially the Municipality of Isulan, is a 1st class municipality in the province of Sultan Kudarat, Philippines. It is the provincial capital of Sultan Kudarat. According to the 2015 census, it has a population of 90,682 people. ^ Census of Population. "Region XII ". Total Population by Province, City, Municipality and Barangay. PSA. Retrieved 20 June 2016.