KASIMOFF, a town of Russia, in the Ryazan government, situated in 54° 56' N. lat. and 41° 3' E. long., 90 miles east-north-east of the government town, on the left bank of the Oka, a tributary of the Volga. It possesses a cathedral, and a mosque supposed to have been built by Kasim. Near the mosque stands a mausoleum built by Shah Ali in 1555. Lying on the direct road from Astrakhan to Moscow and Nizhni Novgorod, Kasimoff is a busy place, with numerous industrial establishments. Of special note are the Kasimoff bells, whose jingle may be heard on the post-horses throughout the country. The waiters in the best hotels of St Petersburg are mostly Kasimoff Tartars. Population, according to St Petersburg Calendar for 1874, 12,027.

Kasimoff existed in the 14th century under the name of the 3feslitcliersk Gorodets or Gorodok (from the Meslitcheryaks, a TurkoFinnish tribe). It was laid completely waste by the Mongolians in 1376, but shortly afterwards rebuilt on a new site. About 1452 the place was bestowed by Basil the Dark on the Tartar prince Kasha who had come to assist him in his wars, and thus became the seat of a Tartar principality or kingdom, which lasted till1677. The last of the line of Rasim accepted Christian baptism, and received the name of Jacob. On his death the principality was incorporated with the empire ; and Peter I. sent a number of the Tartar inhabitants to Voronezh.