Jizera is a river in Bohemia, (Czech Republic). It springs in Jizera Mountains (Liberec Region) and ends in river Labe in Central Bohemia. Its name is - as many other local names in Bohemia - of Celtic origin, because Bohemians (Czechs) of today are Slavonic-speaking descendants of mixture of old Slavons, Celts and Germans.

These are important towns lying on Jizera:

• Semily
• Zelezny Brod
• Turnov
• Mnichovo Hradiste
• Mlada Boleslav
• Benatky nad Jizerou
• Stara Boleslav

There are also other rivers of this old Celtic name like Isar in Bavaria or Isere in France.