Supaul district is one of the thirty-eight districts of Bihar, India. The town Supaul is the district's administrative headquarters. The district, which was split from the former Saharsa district on 14 March 1991, occupies 2,410 km2 (931 sq mi)

Supaul is bounded by Nepal to the north, Araria district to the east, Madhepura and Saharsa districts to the south, and Madhubani district to the west. Supaul district is a part of Kosi division. There are a total of eleven blocks in the Supaul District.

Agriculture is the major occupation of this district and rice is the main crop. There is also an egg farm, which produces approximately 20,000 eggs per day, which was established by M/S Koshi in Parsauni village.

The well-known historical and religious place, namely Durga Sthan, parsarma lies in the Supaul district and it is only 10 km (6 mi) away from the district headquarters.

Rajbiraj (10 km towards north) in Nepal, is a historic city which houses the famous 8th century Rajdevi Temple and close to Chinnamasta shakti Peeth.

Vishnu Mandir, temple based on south Indian architecture and dedicated to lord Vishnu has become a major tourist destination in the district.