59°37′25″N 17°39′10″E / 59.62361°N 17.65278°E
Signhildsberg (historically Fornsigtuna, where forn means ancient, Old Sigtuna, Sithun, Signesberg) is a manor that formerly was a royal estate (Uppsala öd), located in the parish of Håtuna approximately 4 kilometres (2.5 mi) west of the modern town of Sigtuna, by Lake Mälaren in Sweden. Although the location is nearly forgotten, it has a central role in Norse mythology, according to which it was founded by the Norse god Odin.