Jerejak is a 362 hectare island located off the southeastern tip of Penang, Malaysia, a short ferry ride from Bayan Lepas, Penang. It was formerly the main leper asylum for The Straits Settlements (1868), Quarantine Station (1875) and penal colony (1969). Francis Light, the founder of Penang, was said to have arrived in Pulau Jerejak in early 1786 before heading on to Penang. In 1797, Colonel Arthur Wellesley had proposed Jerejak as the possible site for Fort Cornwallis.
His idea of establishing a military post in Jerejak was to offer protection to a new township called Jamestown, which was to be set up in present-day Bayan Lepas. Earlier in 1794, there had been an outbreak of malaria caused most likely by the clearing of the jungle to establish George Town, claiming many lives, including Francis Light himself. Thus, Wellesley was not in favor of the site for Fort Cornwallis to be on Penang Island.
This plan did not materialize as George Town was starting to become a profitable port and it soon became unnecessary to establish Jamestown or have a military facility in that location. As a result of Francis Light's earlier ruling whereby immigrants were allowed to claim whatever land they could clear, Penang became flooded with immigrants. As a precautionary step, these immigrants were sent to Jerejak's health inspection center before they were allowed to proceed to Penang.