Kaliningrad is a city in today's Russia. It is located in the Kaliningrad oblast, a Russian exclave between Lithuania and Poland. Kaliningrad, formerly Königsberg, belonged to Prussia for several centuries and was the northeasternmost major city.
Szczecin (German: Stettin) is a large city in northwestern Poland inhabited by nearly 403,000 people and the capital of the West Pomeranian Voivodeship (Polish: Zachodnio-Pomorskie). Szczecin is located on the Szczecin Lagoon and borders the German states of Mecklenburg-Vorpommern and Brandenburg. The city was part of Prussia for several centuries.
The historical province of Poznan was situated in eastern Prussia from 1815 to 1920. Currently, the territory of the former province is entirely in Poland. The capital was the city of the same name, Posen (present Poznań). About 2 million people inhabited the area.