Sorin Cosoveanu and Mario Pezza provided me with spreadsheets of data retrieved from Atlas Monographique des Communes du Benin , from which I took the 2002 populations and the areas. The totals of populations by department agree with department populations as reported on the INSAE site. The area totals don't agree, but they're mostly not too far off.

Change history:

1999-01-15: Law No. 97-028 , bearing on the organization of the territorial administration of the Republic of Benin, took effect. The resulting division of Benin consists of twelve départements (departments), subdivided into 77 communes, which in turn are divided into arrondissements and finally into villages or city districts.

By comparison with the status quo ante, the twelve departments were each formed by dividing one of the six old provinces in two, without splitting communes. The communes have the same names and territorial extents, but their status before the new law took effect was sub-prefectures and urban circumscriptions. The arrondissements are the same as the former rural and urban communes, except that in Cotonou, Parakou, and Porto-Novo, some of the former urban communes were grouped together to form arrondissements.

Other names of subdivisions:

Abomey: Abomé (Portuguese)
Adjarra: Adjara (variant)
Aguégués: Aguégué (variant)
Akpro-Missérété: Agpro-Missérété (variant)
Boukoumbé: Boukombé (variant)
Cobly: Cobli (variant)
Gogonou: Gogounou (variant)
Klouékanmè: Klouékanmey (variant)
Sèmè-Kpodji: Sèmè-Podji (variant)