SVEABORG, or SWEABORG, a fortified town of the Russian empire, Finland, on seven small islands in the Gulf of Finland, immediately S.E. of Helsingfors, the harbour of which it protects. It has docks and dockyards, and is a station of the Russian fleet, and the chief fortified place in Finland. Pop. 3500. For an account of the bombardment of Sveaborg by the British, June 9, 1855, see Russia.