Porto-Novo is the capital and second-largest city of Benin. The commune covers an area of 110 square kilometres and as of 2002 had a popul…Porto-Novo is the capital and second-largest city of Benin. The commune covers an area of 110 square kilometres and as of 2002 had a population of 223,552 people. 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. It is Benin's second-largest city, and although it is the official capital, where the national legislature sits, the larger city of Cotonou is the seat of government, where most of the government buildings are situated and government departments operate.