Kaliningrad (formerly Königsberg), city in western Russia, on the Pregolya River. The capital of Kaliningrad Oblast, it is a major industrial and commercial centre, connected by channel with Baltiysk, an ice-free port on the Baltic Sea. Industrial plants here manufacture ships, machinery, chemicals, paper, and dressed timber. Historic landmarks in Kaliningrad include the 13th-century castle and a 14th-century cathedral. The German philosopher Immanuel Kant, a native of the city, taught at the university here (now Kaliningrad State University), which was established in 1544.

The city, founded in 1255 as a fortress by the Teutonic Knights, became a member of the Hanseatic League in 1340. From 1457 to 1525 it was the official seat of the grand master of the Teutonic Knights, and from 1525 to 1618 it was the residence of the dukes of Prussia. Frederick I was crowned as the first king of Prussia in the chapel of the castle in 1701. During World War I the city was the scene of heavy fighting between the Germans and the Russians. Following the war it was made the capital of the German province of East Prussia. The city was severely damaged in World War II, and in 1945 after a two-month siege it was occupied by Soviet troops. By agreement between the Allies at the Potsdam Conference (1945) the Union of Soviet Socialist Republics (USSR) annexed the city and surrounding territory. In 1946 the city's name was changed from Königsberg to Kaliningrad, in honour of the Soviet leader Mikhail Ivanovich Kalinin. Population 430,300 (2002).