Jomoro Municipal, which used to be part of the then Nzema East Municipal was created by Legislative Instrument 1394 in 1988.

It is located in the southwestern corner of the Western Region of Ghana. The Administrative Capital of the Municipality is Half Assini.

It is bounded on the south by Latitude 4, 80 N and the Atlantic Ocean {Gulf of Guinea}. It is bounded in the north by Latitude 5, 21 N and the Nini River. It also lies between Longitude 2, 35 W to the East and 3, 07 W to the West. 

The District forms part of the twenty three (23) Metropolitan, Municipalities and Districts in the Western Region.

The District shares boundaries with the Republic of Ivory Coast to the west, to the east with Ellembele District, to the north with Aowin Municipal and to the south with the Gulf of Guinea.

The population of the Municipality according to 2010 population and housing census stands at 150,107 with 73,561 males and 76,546 females.