 The sub-prefectures of the department are Bayota, Dahiépa-Kéhi, Dignago, Dougroupalégnaoa, Doukouyo, Gagnoa, Galebre-Galébouo, Gnagbodougnoa, Guibéroua, Ouragahio, Sérihio, and Yopohué.Gagnoa Department was created in 1969 as one of the 24 new departments that were created to take the place of the six departments that were being abolished.It was created from territory that was formerly part of Centre-Ouest Department.