Subulussalam (Jawoë: سبل السلام) 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 / 2.6423; 98.0041. It covers an area of 1,440 km, 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 km, and including wide swathes of rural areas.

Subulussalam city consists of five administrative districts (kecamatan), tabulated below with their areas and population totals from the 2010 Census and the 2020 Census, together with the official estimates for 2023. The table also includes the number of administrative villages (gampong) in each district, and its postal codes.

Kode Wilayah	Name of District (kecamatan)	Area in km	Pop'n Census 2010	Pop'n Census 2020	Pop'n Estimate 2023	No. of villages	Post codes
11.75.01	Simpang Kiri	213	27,573	35,886	40,640	17	24781
11.75.02	Penanggalan	93	11,479	16,916	19,483	13	24780
11.75.03	Rundeng	369	10,994	14,142	16,017	23	24779
11.75.04	Sultan Daulat	602	12,960	17,126	19,351	19	24783
11.75.05	Longkib	163	4,440	6,681	7,583	10	24782
	Totals	1,440	67,446	90,751	103,074	82

Subulussalam has a tropical rainforest climate (Af) with heavy to very heavy rainfall year-round.

• List of regencies and cities of Indonesia