Onitsha, city, southeastern Nigeria, in Anambra State, on the Niger River, near Enugu. Palm products, corn, nuts, vegetables, and fruits are traded here, and petroleum products, tires, bearings, and nails are manufactured; the city is a source of mineral water. A teachers college for women and a leper colony are in Onitsha; the city is also the residence of the Obi of Onitsha, an Igbo leader. In 1966 it was connected to Asaba by the longest road bridge in the country. Population (1995 estimate) 362,700.