Belait is the largest district (daerah) in Brunei, as well as the western-most. Its capital is Kuala Belait . Other major towns and cities include Badas , Kerangan Nyatan , Labi , Lumut, Seria , Sukang and Telingan .

The district borders the South China Sea to the north, the Bruneian district of Tutong to the east and Malaysia to the south and west.

The Sungai Belait river flows through Belait and it is the longest river in Brunei.

Belait (Seria in particular) is where the majority of Brunei's oil comes from. It has a large expatriate community, including many dutch people. This is due to the fact that Shell Oil has a major presence in the region, and is the sole suplier of Brunei's oil.