Thorsø or Tose is a farm located in the former municipality of Torsnes (until 1910 part of Borge) in Østfold county, Norway. The first written source found about this farm is from 1472, in the form of Tosowe. This is one of three placenames in Østfold that are believed to derive from Old Norse Þórshof and thus indicate an old location for worshipping the Norse god Thor, a temple or "hof". Jan de Vries pointed out in his work on Germanic religion that although instances of placenames derived from Þórshof are fairly common in Norway, they are all grouped around the Oslofjord.