Subulussalam is a city located in the southern part of Aceh province on the island of Sumatra, Indonesia. It is situated inland at the coordinates 2°38′32″N 98°00′15″E and covers a total area of 1,391 km2.
The city was officially declared an independent city on January 2, 2007, following its administrative separation from the Aceh Singkil Regency. Due to its vast territory which includes extensive rural areas, Subulussalam is characterized as the most sparsely populated city in Indonesia, with a population density of approximately 75.9 people per km2 as of 2024.