Nisa is a Portuguese town in the district of Portalegre, Alentejo region and sub-region of Alto Alentejo, with about 3 300 inhabitants.
It is the seat of a municipality with 575.68 km² in area and 7 450 inhabitants (2011), subdivided into 7 parishes.
The municipality is limited to the west and north by the municipality of Vila Velha de Ródão, to the northeast by Spain, to the southeast by Castelo de Vide, to the south by Crato, to the southwest by Gavião, and the northwest by Mação.
