The Penang Strait is an 11 kilometre-wide strait that separates Penang Island from mainland Malay Peninsula. Penang Island is to the west of the channel, while Seberang Perai, the mainland half of the State of Penang, is to the east. The northern and southern ends of the channel join the Strait of Malacca, one of the world's busiest maritime routes. Since the foundation of Penang as a trading outpost of the British Empire in 1786, the Penang Strait has historically been a busy shipping route.