Imo State is one of the 36 states

States of Nigeria

Nigeria is currently divided into 36 states and Abuja, the federal capital territory. The states are further divided into 774 Local Government Areas....

 of Nigeria

Nigeria

Nigeria , officially the Federal Republic of Nigeria, is a federal constitutional republic comprising 36 states and its Federal Capital Territory, Abuja. The country is located in West Africa and shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in...

 and lies to the south of Nigeria with Owerri

Owerri

Owerri is the capital of Imo State in Nigeria, set in the heart of the Igboland. Owerri consists of three Local Govern Areas including Owerri Municipal, Owerri North and Owerri West, it has an estimated population of about 400,000 as of 2006...

 as its capital and largest city.
Imo State came into existence in 1976 along with other new states created under the leadership of the late military ruler of Nigeria, Murtala Muhammad, having been previously part of East-Central State. The state is named after the Imo River

Imo River

The Imo River is located in southeastern Nigeria and flows 150 miles into the Atlantic Ocean. Its estuary is around 40km wide, and the river has an annual discharge of 4km3 with 26,000 hectares of wetland. The Imo's tributary Rivers are the Otamiri and Oramirukwa...

. Part of it was split off in 1991 as Abia State

Abia State

Abia State is a state in southeastern Nigeria. The capital is Umuahia, although the major commercial city is Aba, formerly a British colonial government outpost. The state was created in 1991 from part of Imo State and its citizens are predominantly Igbo people...

, and another part became Ebonyi State

Ebonyi State

Ebonyi State is a mainland south-eastern state of Nigeria, inhabited and populated primarily by Igbo of south eastern Nigeria. Its capital and largest city is Abakaliki. Afikpo is the second largest city. Other major towns are EDDA, Mgbo, Onueke, Ezzamgbo, Nkalagu, Uburu, Onicha, Ishiagu , Ukawu,...

.
The main cities in Imo State are Owerri, Orlu and Okigwe.