The Imo River (Igbo:Imo) is located in southeastern Nigeria and flows 240 kilometres (150 mi) into the Atlantic Ocean. In Akwa Ibom State, the river is known as Imoh River, that is, Inyang Imoh, which translates to River of Wealth (Ibibio: Inyang means river or ocean, and Imoh means wealth). Its estuary is around 40 kilometres (25 mi) wide,^[3] and the river has an annual discharge of 4 cubic kilometres (1.0 cu mi)^[4] with 26,000 hectares of wetland.^[5][6] The Imo's tributary rivers are the Otamiri and Oramirukwa.^[7] The Imo was cleared under the British colonial administration of Nigeria in 1907–1908 and 1911; first to Aba and then to Udo near Umuahia.^[8]

The deity, or Alusi of the river is the female Imo who communities surrounding the river believe to be the owner of the river. Mmiri in Ibo or Igbo language means water or rain.

A festival for the Alusi is held annually between May and July.^[9] The Imo River features an 830-metre (2,720 ft) bridge at the crossing between Rivers State and Akwa Ibom State.^[10] The river god, or Arushi, is a female imo, and the communities surrounding the river believe her to be the river's owner.

Imo river was reported by the world Health Organization as one of the most polluted rivers in Nigeria.^[11]

The river has been said to have coliform bacteria, which makes it unsafe for human consumption.

The major supply of drinkable water for Owerri, the Otamiri River, may dry up if people of the state's capital city continue to pollute it, according to a warning from Imo State Water and Sewerage Corporation.

The General Manager (GM), Emeka Ugoanyanwu, said over the weekend that locals should dispose of trash, urinate, bury the dead, and build soak-away pits along the river.

A project to deliver clean water to Imo residents will also get underway by January, according to the World Bank. Three monarchs from five autonomous communities in the Owerri municipality were present for a roundtable discussion hosted by the Open Arms Initiative for Sustainable Development when Ugoanyanwu made this announcement. He regretted that the city's pipes had been destroyed during the Urban Renewal program of the previous governor Rochas Okorocha's government, making it difficult for tap water to run into the homes of different parts of the city.