Kaliningrad Oblast (Russian: Калинингра́дская о́бласть, romanized: Kaliningradskaya oblast') is the westernmost federal subject of Russia. It is a semi-exclave situated on the Baltic Sea. The largest city and administrative centre of the province (oblast) is the city of Kaliningrad, formerly known as Königsberg. The port city of Baltiysk is Russia's only port on the Baltic Sea that remains ice-free in winter. Kaliningrad Oblast had a population of roughly 1 million in the Russian Census of 2010.