Deluun (Mong. Delүүn) is a somon of Bayan-Ulgiy aimag, Mongolia.
The center of the somon – the village of Rashaant – is located 160 kilometers from the city of Ulgiy, and 1600 kilometers from the capital of the country, Ulaanbaatar.
The somon has a school, a hospital, trade and cultural centers.

Population
The majority of the population are Kazakhs. The population for 2009 is 7133 people.

Geography
The mountains of the Altai Range (up to 3800 meters) stretch from west to south, and the Deluun Range from the north. More than 20 rivers flow through the territory of the sum, there are lakes of glacial origin. There are mountain sheep, wolves, foxes, corsacs, snow leopards.
There are reserves of iron ore, tungsten, coal.

On the territory of the sum there is a large lake – Tal-Nuur.