The source is near Salgótarján in Nógrád county.

The Zagyva is the longest river in Hungary that has both its source and its confluence within the country's borders.

*Sadzava: a river that carries many sediments, see i.e. Czech Sázava.

[1] In Hungarian, the name means 'muddled' (zagyvál(ni): 'to muddle').

This article related to a river in Hungary is a stub.