QasimKhanate or Kingdom of Qasim (Tatar: Qasím xanlığı, Qasím patşalığı; Russian: Касимовское ханство, Касимовское царство) was a Tatar territorial formation (khanate), vassal of Muscovy, which existed from 1452 till 1681 in the territory of modern Ryazan Oblast in Russia with its capital Kasimov, in the middle stream of the Oka River.
The land was settled by Mishar Tatars (the descendants of the earliest Turkic population), Russians, and Mordvins.
Moscow's administrators elected the khans from ruling families of the Tatarkhanates: Khanate of Kazan, the Crimean Khanate, and the Siberian Khanate.
The Khanate existed in the 15th and 16th centuries in the area adjacent to the mouth of the Volga river, where the contemporary city of Astrakhan is now located.
The North-Western Caspian seaside was a southern boundary and the Crimean Khanate bounded Astrakhan on the west.
Ivan dispatched soldiers to Astrakhan, establishing Darwish Khan as a vassal ruler of the Astrakhan Khanate in 1554.