Jan Mayen Island is a volcanic island in the Arctic Ocean and part of the Kingdom of Norway. It is 55 km (34 mi) long (southwest-northeast) and 373 km² (144 mi²) in area, partly covered by glaciers (an area of 114.2 km² or 44.1 mi² around the Beerenberg). It has two parts: larger northeast Nord-Jan and smaller Sør-Jan, linked by an isthmus 2.5 km (1.6 mi) wide. It lies 600 km (about 400 mi) northeast of Iceland, 500 km (about 300 mi) east of central Greenland and 1,000 km (about 600 mi) west of the North Cape, Norway. The island is mountainous, the highest summit being the Beerenberg volcano in the north. The isthmus is the location of the two largest lakes of the island, Sørlaguna (South Lagoon), and Nordlaguna (North Lagoon). A third lake is called Ullerenglaguna (Ullereng Lagoon). Jan Mayen was formed by the Jan Mayen hotspot.

A regulation dating from 2010 renders the island a nature reserve under Norwegian jurisdiction. The aim of this regulation is to ensure the preservation of a pristine arctic island and the marine life nearby, including the ocean floor. Landings at Jan Mayen can be done by boat. Nonetheless, this is permitted only at a small part of the island, named Båtvika (Boat Bay). As there is no commercial airline operating at the island, one cannot get there by plane, except charter plane. Admission for landings by a charter plane has to be obtained in advance. Admission to stay on the island has to be obtained in advance, and is generally limited to a few days (or even hours). Putting up a tent or setting up camp is prohibited. There is a separate regulation for the stay of foreigners.

Jan or JAN may refer to: