However, in 2000, Duékoué, Guiglo, and Toulépleu Departments were split-off from Dix-Huit Montagnes to form Moyen-Cavally Region.

At the time of its dissolution, Dix-Huit Montagnes was divided into six departments: Bangolo, Biankouma, Danané, Kouibly, Man, and Zouan-Hounien.

Dix-Huit Montagnes was traversed by a northwesterly line of equal latitude and longitude.

Dix-Huit Montagnes was abolished as part of the 2011 administrative reorganisation of the subdivisions of Ivory Coast.

The territories of the departments of Biankouma, Danané, Man, and Zouan-Hounien become Tonkpi Region.