What was the unusual about territory of Prussia as it existed in 1865?

In 1865, the territory of Prussia consisted of two noncontiguous parts, making it geographically unusual among major political entities. The main part of Prussia, known as East Prussia, was located on the Baltic Sea coast, while the smaller western part, known as West Prussia, was located south of the Baltic, surrounded by other German states. This geographical quirk was a result of historical developments, including partitions of Poland in the 18th century.