Longyearbyen is the largest settlement and the administrative centre of Svalbard. It is located on the western coast of Spitsbergen, the largest island of the Svalbard archipelago, on the southern side on Adventfjorden , which continues inland with Adventdalen (English: the Advent valley). The Governor of Svalbard and his administration reside in Longyearbyen.

Longyearbyen has approximately 2,060 inhabitants (at the end of 2007). It is the world's most northerly town, and the most northerly settlement with a population greater than 1,000.