Which Russian oblast forms a border with Poland?

The Russian oblast of Kaliningrad forms a border with Poland due to its unique geographic location. Situated between Lithuania and Poland, Kaliningrad is an exclave of Russia, separate from the rest of the country by several hundred kilometers. It borders Poland to the south and shares a maritime border with Lithuania to the east. This distinctive placement of Kaliningrad is a result of complex historical factors including the aftermath of World War II, when the region was annexed by the Soviet Union and separated from the main parts of Russia.