Onitsha (Ọ̀nị̀chà Mmílí or simply Ọ̀nị̀chà) is a city on the eastern bank of the Niger River, in Anambra State, Nigeria. A metropolitan city, Onitsha is known for its river port and as an economic hub for commerce, industry, and education. It hosts the Onitsha Main Market, the largest market in Africa in terms of geographical size and volume of goods.
As of 2016, Onitsha had an estimated city proper population of 1,080,000 people. As of early 2022, Onitsha has a rising estimated population at 1,623,000. The indigenous people of Onitsha are Igbos and speak the Igbo language. The Onitsha people are referred to as Ndi Onicha.
Onitsha Ado na Idu was originally known as Onitsha Mmili. The people of Onitsha originally lived in communities scattered across Western Igbo (Delta and Edo states) and emigrated to the place called Onitsha today where they established a community.
After their arrival on the east bank (Onicha-mmili, "Onitsha-on-water", see above), the community gradually became a unitary kingdom, evolving from a loosely organized group of "royal" villages (Umu Ezechima) to encompass "non-royal" villages (Onicha Ebo Itenani).
Onitsha slowly grew to become an important trading port for the Royal Niger Company in the mid-1850s following the abolition of slavery and with the development of the steam engine when Europeans were able to move into the hinterland.
Trade in palm kernels, palm oil, and other cash crops on the coast of the Bight of Biafra increased around this river port in the 19th century.
In 1857 British palm oil traders established a permanent station in the city with Christian missionaries joining them, headed by the liberated African bishop Samuel Ajayi Crowther (a Yoruba recaptive) and Reverend John Taylor (an Igbo recaptive).
In 1900 Onitsha became part of a British protectorate. The British colonial government and Christian missionaries penetrated most of Igboland to set up their administration, schools and churches through the river port at Onitsha.
In 1965, the Niger River Bridge was built across the Niger River to replace the ferry crossing.