The Blanice river is the right tributary of the Otava river. They join each other near the small village Putim about 5 km south of the town Písek. The Blanice river springs on the northern slope of Knížecí Stolec mountain (1,226 m) about 15 km south-west of the town Volary.

Blanice runs through the hilly country with many narrow valleys (canyons) on the upper reaches of the river. One of the most beautiful parts has been preserved below the ruins of the Hus castle. This part along the river, between the small village Arnoštov and the Hus castle, has been protected in the nature reserve called Horní Blanice (Upper Blanice).
The flow of the river was dammed near the town Husinec by the Husinec Dam. The reservoir, which arose behind the dam, is used as a source of drinkable water for the town Prachatice.
The valley opens behind the dam, it becomes shallower and the river runs through the village Strunkovice nad Blanicí and the small town Bavorov. Then Blanice flows through the towns Vodňany and Protivín through a flat country to the confluence with the Otava river.

The Blanice river has the big slant and it has ample of water in summer. It was used for floating timber from the region around Volary. The river was considered to be auriferous and the gold-washing developed on its banks in the Middle Ages and it was a well-known habitat of pearl-oysters. The length of the river is 95 km and its river basin is 860.5 square km large.

Several tourist trails lead along the river. The most important part with the nature reserve Horní Blanice is accessible along the red marked trail (Volary - Zbytiny - Lhenice), green marked one (Volary - Arnoštov - Prachatice) or blue marked one (Volary - Křišťanovice - Chroboly). The yellow marked path runs along the part of the Blanice between the village Záblatí and Husinec.