Sverresborg or Sverre Sigurdsson's castle was a fort and residence built in the medieval city of Nidaros by King Sverre Sigurdsson. The fortification was built in support of Sverre Sigurdsson's struggle against his rival King Magnus Erlingsson to claim the throne of Norway. The site now forms part of the Sverresborg Trøndelag Folk Museum, an open-air museum for the region of Trøndelag.