Nacka Municipality (Swedish: Nacka kommun) is a municipality in Stockholm County in east-central Sweden. Its seat is located at Nacka. The municipality is situated just east of the Swedish capital, Stockholm, and its western parts are considered a suburban part of the city of Stockholm.
The present municipality was created in 1971 when the City of Nacka (itself instituted in 1949) was amalgamated with Saltsjöbaden (itself detached from "old" Nacka in 1909) and Boo.
Saltsjöbanan (lit. 'the Salt Sea Line') is an electrified suburban rail system between Stockholm and Saltsjöbaden in Nacka, Sweden. It is 18.5 kilometres (11.5 mi) in length and has eighteen stations in use. An average of 17,200 boardings are made on an ordinary workday (2019). The line is mostly single-track (with passing loops between Nacka and Saltsjö-Järla, and between Storängen and Saltsjö-Duvnäs), and is isolated from Sweden's national railway network, although both are built to compatible 1,435 mm (4 ft 8+1⁄2 in) standard gauge. The Storstockholms Lokaltrafik (SL) classifies it as "light rail" in its maps.
From January 2023 until December 2024, the entire Saltsjöbanan was closed for reconstruction, after the westernmost section from Henriksdal to Slussen had already been suspended since 2016. Services partially resumed on 15 December 2024 between Saltsjö-Järla and Saltsjöbaden as well as between Igelboda and Solsidan, with full service beyond Saltsjö-Jarla to Slussen planned for 2028.