Borneo is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and east of Sumatra. The island is politically divided among three countries: Malaysia and Brunei in the north, and Indonesia to the south.

Północna część należy do Malezji. Są to stany Sarawak i Sabah. Niewielki obszar (ok. 5 tys. km²) pomiędzy Sarawak i Sabah zajmuje Brunei, reszta zaś to terytorium Indonezji.