Preparis is an island located between the Bay of Bengal and the Andaman Sea, 77 km to the NNE of the Coco Islands and 133 km to the SSW from Cape Negrais, the nearest point in the coast of Burma. The island makes up the northern end of the Andaman Islands chain. The island is 7 km long and has a maximum width of 1.8 km. It is covered with dense forest and has gentle slopes rising to a maximum height of 81 m.