a British island in the strait of Bab-el-Mandeb, at. the entrance to the Red Sea, and 96 m. W. by S. of Aden. Perim is 2 m. from the Arabian shore, is about 31 m. long with an average breadth of over a mile and covers some 7 sq. m. There is a good harbour with easy entrance on the south side with a depth of water from 25 to 30 ft. It is largely used by mercantile vessels as a coaling-station and for taking in stores,, including fresh water and ice. Perim, the Diodoros island of the Periplus, was, in consequence of the French occupation of Egypt, garrisoned from 1799 to 1801 by a British force. In view of the construction of the Suez Canal and the increasing importance of the Red Sea route to India the island was annexed to Great Britain in 1857, fortified and placed under the charge of the Aden residency. In 1861 a lighthouse was built at its eastern end. Submarine cables connect the island with. Aden, Egypt and Zanzibar. Population, including a garrison. of 50 sepoys, about 200.