Sumisip, officially the Municipality of Sumisip, is a municipality in the province of Basilan, Philippines. According to the 2020 census, it ha…Sumisip, officially the Municipality of Sumisip, is a municipality in the province of Basilan, Philippines. According to the 2020 census, it has a population of 47,345 people. 12 barangays that were not on Basilan Island seceded to form the municipality of Tabuan-Lasa through Muslim Mindanao Autonomy Act No. 187, which was subsequently ratified in a plebiscite held on March 29, 2008.