Subulussalam is a city in the south of Aceh province of Indonesia. It is located inland on the island of Sumatra. On 2 January 2007, the provincial government of Aceh declared Subulussalam to be an independent city as a result of the administration being separated from that of Aceh Singkil Regency. of which it was formerly a part. It is located at 2°38′32″N 98°00′15″E / 2.6423°N 98.0041°E. It covers an area of 1,440 km², and it had a population of 67,446 at the 2010 Census and of 90,751 at the 2020 Census; the official estimate as in 2023 was 103,074. As a result, Subulussalam is the most sparsely-populated city in Indonesia, with an overall population density in 2023 of only 71.6 people per km², and including wide swathes of rural areas.