[2][3] Situated on an inlet of the Gulf of Guinea, in the southeastern portion of the country, the city was originally developed as a port for the transatlantic slave trade led by the Portuguese Empire.

Porto-Novo was once a tributary of the Yoruba kingdom of Oyo,[4][5] which had offered it protection from the neighbouring Fon, who were expanding their influence and power in the region.

[9] In 1861, the British, who were active in nearby Nigeria, bombarded the city, which persuaded the Kingdom of Porto-Novo to accept French protection in 1863.

[citation needed] Under French colonial rule, flight across the new border to British-ruled Nigeria in order to avoid harsh taxation, military service and forced labour was common.

A combination of the aforementioned facts, coupled with the fact that the city itself lies within the sphere of Nigerian socioeconomic influence, have given Porto-Novians a preference for some measure of bi-nationality or dual citizenship, with the necessary linguistic consequences; for example, Nigerian home video films in Yoruba with English subtitles have become popular in Porto-Novo and its suburbs.

[citation needed] Benin's parliament (Assemblée nationale) is in Porto-Novo, the official capital, but Cotonou is the seat of government and houses most of the governmental ministries.

[citation needed] The city is home to a branch of the Banque Internationale du Bénin, a major bank in Benin, and the Ouando Market.

The city’s location on the edge of the Dahomey Gap makes it much drier than would be expected so close to the equator, although it is less dry than Accra or Lomé.

[citation needed] The music is also played in the city's Roman Catholic churches, but the royal bird crest symbol has been replaced with a cross.