It is formed by the confluence of the Kamenice and Žirovnice rivers in Jarošov nad Nežárkou.

The Nežárka itself is formed by the confluence of the Kamenice and Žirovnice in Jarošov nad Nežárkou, and is 56.0 km (34.8 mi) long.

In a broader point of view, the Nežárka (as Kamenice) originates in the territory of Těmice in the Křemešník Highlands, on the slope of the Bohutín hill at an elevation of 669 m (2,195 ft) and flows to Veselí nad Lužnicí, where it enters the Lužnice River at an elevation of 407 m (1,335 ft).

[3] The sources and longest tributaries of the Nežárka are:[4] The most notable settlement on the river is the town of Jindřichův Hradec, other settlements on the river are Jarošov nad Nežárkou, Rodvínov and Stráž nad Nežárkou.

There are 528 bodies of water larger than 1 ha in the basin area and many smaller.