Přírodní park Povodí Kačáku, Nature park in Prague-West and Kladno districts, Czech Republic.

Povodí Kačáku is a nature park located across Prague-West, Kladno, and Beroun districts, characterized by deep valleys and forested hillsides. The landscape is shaped by the Kačák River and its tributaries, which flow through steep terrain creating natural corridors through the woodland.

The area was first protected in 1988 as a nature park covering 4,673 hectares. In 2010 the park was re-declared by the Central Bohemian Region and enlarged to take in part of the former Studánka military training ground in the Brdy hills, which now forms its western edge alongside the Křivoklátsko Protected Landscape Area.

The Kačák valley below Mostecký Mill became a tramping area in the First Republic. The Batalion settlement was founded in 1928 below Markův Mill, and Údolí oddechu in 1930 hosted sports tournaments into the 1980s. Painter Karel Souček often visited Rujana and donated his paintings as raffle prizes.

A network of marked hiking trails runs through the park, making exploration of the valleys and forests straightforward. The red-marked trail 0029 follows the Kačák stream and serves as a main route for visitors wanting to experience the river gorge.

On Vysoký vrch (486 m) stands an 8-metre wooden lookout tower, reached by a ladder with 17 rungs and built in 2007; the earlier tower appeared in the 1997 film Báječná léta pod psa. Archaeologist Jiří Waldhauser identified a hillfort probably from the late Bronze and Hallstatt periods there in the mid-1980s.