Petrozavodsk (Russian: Петрозаво́дск; IPA: [pʲɪtrəzɐˈvotsk]; Karelian/Vepsian/Finnish: Petroskoi) is the capital city of the Republic of Karelia, Russia. It stretches along the western shore of the Lake Onega for some 27 kilometers (17 mi). Population: 263,540 (2010 Census preliminary results); 266,160 (2002 Census); 269,485 (1989 Census).

It is served by Petrozavodsk Airport.

On September 11, 1703, Prince Menshikov founded the settlement of Petrovskaya Sloboda ("Petrine Sloboda"). He did so at the behest of Tsar Peter the Great, who needed a new iron foundry to manufacture cannons and anchors for the Baltic Fleet at the time of the Great Northern War (1700–1721). At first the foundry used the name Shuysky zavod (literally, "factory at the Shuya River"), but a decade later it became Petrovsky zavod ("Petrine factory"), after the name of the reigning monarch. From this form the present name of the city derives.

By 1717, Petrovskaya Sloboda had grown into the largest settlement in Karelia, with about 3,500 inhabitants, a timber fort, a covered market, and miniature palaces of the Tsar and Menshikov. The town's best-known landmark became the wooden church of Saints Peter and Paul, rebuilt in 1772 and renovated in 1789. The church retained its original iconostasis until this relic of Peter's reign was destroyed by fire on October 30, 1924.