Casamance (French pronunciation: [kɑ.za.mɑ̃s], Portuguese: Casamansa[kɐzɐˈmɐ̃sɐ]) is the area of Senegal south of the Gambia including the Casamance River. It consists of Basse Casamance (Baixa Casamança, Lower Casamance i.e. Ziguinchor Region) and Haute Casamance (Alta Casamança, Upper Casamance i.e. Kolda Region and Sédhiou Regions). The largest city of Casamance is Ziguinchor.
The Casamance was subject to both French and Portuguese colonial efforts before a border was negotiated in 1888 between the French colony of Senegal and Portuguese Guinea (now Guinea-Bissau) to the south. Portugal lost possession of Casamance, then the commercial hub of its colony. Casamance, to this day, has preserved the local variant of Upper Guinea Creole known as Ziguinchor Creole, and the members of the deep-rooted Creole community carry Portuguese surnames like Da Silva, Carvalho and Fonseca. The historical ties to Portugal were a factor in Senegal's decision to seek membership of the Community of Portuguese Language Countries (CPLP), becoming an associate observer in 2008. Interest in Portuguese heritage has been revived in order to exert a distinct identity, particularly in Baixa Casamança.