Gdynia is a city in northern Poland and a seaport on the Baltic Sea coast. With an estimated population of 257 000, it is the 12th-largest city in Poland and the second-largest in the Pomeranian Voivodeship after Gdańsk. Gdynia is part of a conurbation with the spa town of Sopot, the city of Gdańsk, and suburban communities, which together form a metropolitan area called the Tricity with around one million inhabitants.