The Ay (Bashkir: Әй, Äy; Russian: Ай) is a river in Bashkortostan and Chelyabinsk Oblast in Russia, a left tributary of the Ufa. The river is 549 kilometres (341 mi) long, and its drainage basin covers 15,000 square kilometres (5,800 sq mi).^[1] The Ay freezes up in late October or early November and remains icebound until mid-April. The cities of Zlatoust and Kusa are along the river Ay. There are many steep cliff sides and caves along the banks of the river.^[2] The current of the Ay has been used for generating hydroelectric power. It is also possible to fish for pike, bleak, and carp, to name a few species.^[3]

This article includes content derived from the Great Soviet Encyclopedia, 1969–1978, which is partially in the public domain.