Saint Petersburg (Russian: Санкт-Петербург, tr. Sankt-Peterburg; IPA: [sant pʲɪtʲɪrˈburk] ( listen)) is a city and a federal subject (a federal city) of Russia located on the Neva River at the head of the Gulf of Finland on the Baltic Sea. In 1914 the name of the city was changed to Petrograd (Russian: Петроград; IPA: [pʲɪtrɐˈgrat]), in 1924 to Leningrad (Russian: Ленинград; IPA: [lʲɪnʲɪnˈgrat]), and in 1991, back to Saint Petersburg.

In Russian literature, informal documents, and discourse, the "Saint" (Санкт-) is usually omitted, leaving Petersburg (Петербург, Peterburg). In common parlance Russians may drop "-burg" (-бург) as well, referring to it as Peter (Питер, Russian: [ˈpʲitʲɪr]).

Saint Petersburg was founded by the Tsar Peter the Great on May 27 [O.S. 16] 1703. From 1713 to 1728 and from 1732 to 1918, Saint Petersburg was the Imperial capital of Russia. In 1918 the central government bodies moved from Saint Petersburg (then named Petrograd) to Moscow. It is Russia's second largest city after Moscow with almost 5 million inhabitants and the fourth most populated federal subject. Saint Petersburg is a major European cultural center, and also an important Russian port on the Baltic Sea.