The Zagyva is a river in Hungary. Its length is 160 km, and drains an area of about 5,677 km². The source is near Salgótarján in Nógrád county. It flows through the towns of Bátonyterenye, Pásztó, Hatvan and Jászberény and flows into the Tisza River at Szolnok. Average discharge at Szolnok is 9 m³/s.