During spring of 2016 a number of large presumed house terraces were identified by the authors at Korshamn. As a consequence high resolution geophysical surveys using ground-penetrating radar were carried out in September 2016. Korshamn is one of the main harbour bays of the island of Björkö, situated outside the town boundaries of the Viking town of Birka. The survey revealed a major Viking period hall on the site, with a length of around 40 meters. Based on the land upheaval the area of the Viking hall can be dated to sometime after 810 AD. The hall is connected to a large fenced area that stretches towards the harbour basin.