Rajčanka or Rajčianka (Hungarian: Rajcsánka) is a river in northern Slovakia springing in Strážovské vrchy near Čičmany and pouring into Váh in Žilina. It is 46.6 km (29.0 mi) long and its basin size is 359 km (139 sq mi).

It forms the border of Lúčanská Malá Fatra Mountains and of Strážovské vrchy. 32 km of its length are navigable.

Cities along its course are: Rajec, Rajecké Teplice, Žilina.

Names and etymology

The original name of the river was Lietava, later Žilinka and only after the founding of Rajec (the 14th century) also Rajčanka (see also Etymology of Rajec).