Plzeň Region is an administrative unit (kraj) in the western part of Bohemia in the Czech Republic. It is named after its capital Plzeň. In terms of area, Plzeň Region is 7,561 km2, the third largest region in the Czech Republic. However, with a population of about 585,000 inhabitants it is only the ninth most populous region. After the South Bohemian Region it is the second least densely populated region. The region can be roughly divided into two parts: a highly industrialized north-eastern part with a strong engineering tradition around Pilsen and a more hilly and rural south-western part with smaller-sized manufacturing companies processing natural resources.

Plzeň, also known in English and German as Pilsen, is a city in the Czech Republic. About 78 kilometres west of Prague in western Bohemia, it is the fourth most populous city in the Czech Republic with about 181,000 inhabitants, and about 323,184 people in its urban area.