Tinjil is a small island located in the Indian Ocean. Administratively, this island is included in the area of Pandeglang Regency, Banten.
Since 1988, Tinjil Island has been used as a natural breeding ground for long-tailed monkey species (Macaca fascicularis).
Pandeglang Regency (Sundanese: Kabupatén Pandéglang; pronounced [kabuˌpat̪ɛn panˈdeɡlaŋ]) is a regency of Banten province, Indonesia. It is mainly located on the west and south coasts of the island of Java and is the most westerly regency on Java Island, but it also includes several offshore islands such as Panaitan, Peucang, Deli and Tinjil. It is bounded by Serang Regency to the north, Lebak Regency to the east, the Java Sea (part of the Indian Ocean) to the south, and the Sunda Strait (separating Java from Sumatra) to the west. The regency has a land area of 2,746.81 km, and a population at the 2010 Census of 1,149,610, rising to 1,272,687 at the 2020 Census; the official estimate as of mid-2024 was 1,437,046 (comprising 738,650 males and 698,396 females). The regency seat is the town of Pandeglang in the northeast of the regency, at the centre of a more densely populated region close to Greater Jakarta, while outside of that northeast agglomeration the principal centre is the town of Labuan on the west coast.