Aba is a city in Nigeria, located on the Aba River . Originally settled by the Ibo Tribe, it eventually became the administrative center of Britain's colonial government. It was a major commercial center in Abia state in south-eastern Nigeria. In 1929 it was the site of revolt by women, in protest of colonial taxation policy. In 1967 the capital of the short-lived secessionist state of Biafra was moved to Aba from Enugu as Nigerian troops advanced into Biafra. The city of Aba has a population of about 257,300 (1990 est.).