Katsina (kätsēˈnə, kätˈsĭnə) [key], city (1991 est. pop. 182,000), N Nigeria, near the Niger frontier. The city, surrounded by a wall 13 mi (21 km) long, is the trade center for an agricultural region where guinea corn and millet are grown for home consumption, and peanuts, cotton, and hides are produced commercially. The city has a steel-rolling and vegetable oil mills. Leather handicrafts are made in Katsina. In the 17th and 18th cent. it was the largest of the seven Hausa city-states and the cultural and commercial center of Hausaland. In 1807, Katsina was conquered by the Fulani and lost to Kano its preeminent position among Hausa cities. The city is the site of Katsina Training College and Gobaru Tower mosque.