Mastník, Brook in Central Bohemian Region, Czech Republic

Mastník is a 49.5 km brook in the Central Bohemian Region, a right-bank tributary of the Vltava. It rises near Střezimíř at 597.6 m, feeds the Velký Mastník pond, passes Sedlčany and Osečany, and below Radíč cuts a narrowing wooded valley before entering the Slapy reservoir at 271 m.

Mastník is a brook in Central Bohemia, a right tributary of the Vltava. Its upper course was called Zlatý potok in the 17th century; later its water powered 32 mills and sawmills along the stream. The settlement of Ústí at its mouth, together with Borákov and Kobylníky, was flooded in 1955 by the Slapy reservoir.

The brook gave its name to the village of Mastník and to the Velký Mastník and Malý Mastník ponds near Martinice. In the 17th century its upper course before Sedlčany was called Zlatý potok (Golden Brook); later its water powered 32 mills and sawmills. Since 1987 an Easter Sunday canoe descent runs the 10 km from Sedlčany to Radíč.

The brook can be accessed from rural roads that cross the countryside at several points along its course. Water levels change with the seasons, so conditions vary depending on when you visit.

The lower course below Radíč was flooded by the Slapy reservoir, turning the former valley into a roughly 4 km long narrow bay of the Vltava. The Celtic oppidum Hrazany stood on the promontory between the Vltava and the Mastník, and the medieval Ostromeč castle later rose nearby.