The southern regions of Benin receive two seasons of rainfall from March to July and September to November, while the northern regions of the country receive one season of rainfall from May to September.

[2] The department has mostly low-lying sandy coastal plains towards the Atlantic Ocean, marshes, lagoons and lakes.

[3] Ouidah is the departmental capital; other major settlements include Abomey-Calavi, Allada, Ganvie, Godomey, Kpomassè, Sô-Ava, Toffo, Togoudo, Tokpa-Domè, Tori-Bossito and Zè.

Petroleum was discovered in the 1960s in offshore areas, while titanium, low quality iron ore, ilmenite and chromite are the major minerals.

[4] According to Benin's 2013 census, the total population of the department was 1,398,229, with 686,747 males and 711,482 females.

[7] Atlantique is subdivided into eight communes, each centered at one of the principal towns: Abomey-Calavi, Allada, Kpomassè, Ouidah, Sô-Ava, Toffo, Tori-Bossito and Zè.

A law passed in 1999 transformed the sous-prefectures, the lowest level of territorial administration, into local governments.

[8] Municipalities and communal councils have elected representatives who manage the administration of the regions.