Plzeň or Pilsen is a ceety in wastren Bohemie in the Czech Republic. It is the caipital o the Plzeň Region an the fowert maist populous ceety in the Czech Republic. It is locatit aboot 90 km wast o Prague at the confluence o fower rivers—the Radbuza, the Mže, the Úhlava, an the Úslava—which furm the Berounka River.