The Svalbard and Jan Mayen category exists only for the purpose of ISO 3166 that somehow have one entry for the two areas.
Jan Mayen is a small island in the North Atlantic.
Svalbard is an archipelago located in the Arctic Ocean. The islands lie between latitude 74° and 81° North and between longitude 10° and 35° East. The archipelago is composed of Spitsbergen, North East Land Nordaustlandet, Edgeøya (Edge Island), Barentsøya (Barents Island), Prins Karls Forland, Kvitøya (Kvit Island), Kong Karls Land (Wiche Islands), Bjørnøya (Bear Island), and Hopen.