The Ogosta (Bulgarian: Огоста [oˈɡɔstɐ], Latin: Augusta), is the largest river in Northwestern Bulgaria, a right tributary of the Danube.

The towns of Chiprovtsi, Montana, and Miziya are situated on the river's banks.

[2] The average water discharge in the lower course of the river is 18 cubic meters per second.

Other than that, there were intensive mining activities along the river between 1950 and 1999, and factories also produced pollution.

[2] The major sources of income the river provides are for farmers and animal herders.