Forsmark is a village with 59 inhabitants on the east coast of Uppland, Sweden. It is most known as the location of the Forsmark Nuclear Power Plant.
Another remarkable facility in Forsmark is the static inverter of HVDC Fenno-Skan, just west of the nuclear power plant.
Because of the sensitive instruments located in the nuclear power plant for the purpose of detecting local leaks, Forsmark was, on April 27, 1986, the first place outside the Soviet Union where the signs of the Chernobyl accident became apparent. When workers at the plant were found to carry radioactive particles, the origin of the leak was investigated and it eventually became clear that the contamination came from the atmosphere rather than from the Forsmark plant itself.
Forsmark formerly had an ironworks producing oregrounds iron.