Sigtuna is a locality situated in the eponymous Sigtuna Municipality, in Stockholm County, Sweden with 9,689 inhabitants in 2020. It is the namesake even though the seat of the municipality is in another locality, Märsta. Sigtuna is for historical reasons still often referred to as a stad. Sigtuna is situated at the bay Skarven, stretching around Upplands-Bro and a part of Lake Mälaren. Present-day Sigtuna, a harbour town that was established around 980, developed about 4 kilometres (2.
https://en.wikipedia.org/wiki/Sigtuna