Jerejak, or Pulau Jerejak (English: Jerejak Island), 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.
In 1868, a leper asylum was completed but only in used in 1871. The cost of construction was supported by the local community. In 1880, it was expanded becoming the collection center of leprosy (leprosarium) for the Straits Settlements until 1930s.The leprosarium was closed in 1960s and the inmates were transferred to Sungai Buloh Leper Settlement/Leprosarium. Part of the island was made a health quarantine center for immigrants in 1875 at the eastern and northern parts of the island.
A memorial is located in the island dedicated to two crew members of the Imperial Russian Navy who died when their cruiser Zhemchug was sunk by the cruiser SMS Emden of the Kaiserliche Marine in the Battle of Penang on 28 October 1914. This is one of the few incidences of action which took place in Malaysian territory during World War I.  
After World War II, there was an increase in the number of tuberculosis patients and a sanatorium was set up in Jerejak for victims. On 12 June 1969, the Jerejak Rehabilitation Centre was set as a maximum security prison, hence earning the island the moniker, the Alcatraz of Malaysia. The centre was eventually closed in August 1993. 
Jerejak Resort & Spa is located at the beautiful tropical island of Pulau Jerejak set amidst rich diversity of flora and fauna. Located in between Penang Island and the Penang Mainland, Jerejak Resort and Spa is a wonderful stopover when you visit the Northern hub of Malaysia. Together with its colorful and rich historical background, it is a wonderful place for holidays. The small island boast many ancient emerald environment which are known to be older than the equatorial forests of the Amazon or the Congo with an ecosystem that is both inspiring and engaging.
The Jerejak Island situated on a 362 ha island, just 10 minutes away from the hustle & bustle of Penang Island, west coast of Peninsular Malaysia. From there, take a 5 minutes ferry ride to Jerejak Island. Ferry ticket must be purchased from the ticket counter at the jetty. RM25 per adult and RM16 per child (two way transfer).
Plans were made to redevelop Jerejak into a resort in 2000 and this resulted in the closure of the more "unsavoury" institutions in the island like the sanatorium and prison. In January 2004, the Jerejak Resort & Spa was opened for business. The resort was built over the area once occupied by the leprosarium.
This development remains somewhat controversial with concerns about the systematic removal of the island's historical remains and heritage  and the impact on Jerejak's fragile eco-system.