The Kirzhach River (Russian: Киржа́ч) is a river in the Vladimir Oblast in Russia, a left tributary of the Klyazma River. The length of the river is 133 km. The area of its drainage basin is 1820 km². The Kirzhach River originates at the confluence of the Bolshoi Kirzhach River and the Maly Kirzhach River near Ivashevo Village. The river flows from north to south and empties into the Klyazma at Gorodishchi. The Kirzhach is a shallow river with a maximum depth of 4 m and a maximum width of 70 m. It is not navigable for larger vessels, however it is very popular for canoeing and kayaking. Its major tributary is the Sheredar' River. The towns of Kirzhach and Gorodishchi are located on the shores of the Kirzhach.
The name is from Mordvin: Erzya: кяржи, Moksha: керш 'left' (sc. tributary).