Together with the Mže, which is its main source, the Berounka is 244.6 km (152.0 mi) long, which makes it the fifth longest river in the Czech Republic.

Originally, the entire stream was called Mže (German: Mies) and the name first appeared in the 12th century, among others in Chronica Boemorum.

[3] In the Czech Republic, it is 242.23 km (150.51 mi) long, which makes it the fifth longest river in the country.

After its confluence with the Radbuza in Plzeň, the Berounka flows through Beroun, Řevnice, Dobřichovice, Černošice and along the edge of Prague.

[4] The river is home to the mollusc Unio pictorum, which is critically endangered within the Czech Republic.

It is popular thanks to the sections in the protected landscape areas of Křivoklátsko and Český kras, which lead through unspoiled nature.