Tutong District (; Jawi: دائيره توتوڠ) or simply Tutong is one of the four districts of Brunei. It has an area of ; the population was 48,313 in 2016. The administrative town is Pekan Tutong. It is home to Tasek Merimbun, the country's largest natural lake. History Prior to the introduction of the British residential system in Brunei in 1906, Tutong was a land, a type of land ownership in Brunei's traditional government. It was the non-hereditary land of , one of the four traditional (viziers) to the Sultan. The district have seen a rapid rise in population by nearly 15,000 in 1967. Geography The district borders the South China Sea to the north, Brunei-Muara District to the north-east, the Malaysian state of Sarawak to the east and south, and Belait District to the west. With an area of , it is the third largest district in Brunei. The Tutong River is the sole primary river and only flows in the district. It begins in the district's interior in the south and flows northwards which finally discharges into the South China Sea. ("Bedawan Hill") is the highest point in the district with a height of . The district is home to Tasek Merimbun, the largest natural lake in Brunei. It is a designated ASEAN Heritage Park since 29 November 1984. Administration Tutong District is administered by Tutong District Office (), a government department under the Ministry of Home Affairs. The district is divided into eight mukims: Mukim Keriam Mukim Kiudang Mukim Lamunin Mukim Pekan Tutong Mukim Rambai Mukim Tanjong Maya Mukim Telisai Mukim Ukong Mukim Pekan Tutong encompasses the municipal area of Pekan Tutong. According to the Constitution, the district is to be represented in the Legislative Council, the state legislature, by up to 3 members. As of 2017, two members have been appointed to represent the district in the legislature. Demographics Tutong District is the third most populous district in Brunei. According to the 2016 census update, the population was 48,313 and made up about 11.6% of the country's total population. were males and were females. The racial make-up were as follow: were Malays, were Chinese, and were those other than the aforementioned races. In terms of residency status, were citizens, were permanent residents and were temporary residents. In terms of professed religions, were Muslims, were Christians, were Buddhists, and professed other than the aforementioned religions or irreligious. The