When it comes to Mainland Portugal, we can clearly define that the districts of Portugal are the most viable first-level administrative subdivisions. As per recent records, mainland Portugal has been segregated into eighteen districts.

In fact, with respect to the administrative terms, the nation is separated into two autonomous areas- the Madeira and Acores form the first region while the eighteen districts are grouped under the second. The eighteen districts are Lisbon, Leiria, Santarém, Setúbal, Beja, Faro, Évora, Portalegre, Castelo Branco, Guarda, Coimbra, Aveiro, Viseu, Bragança, Vila Real, Porto, Braga and Viana do Castelo. A separate civil governor is appointed for each of these districts. The elected representatives serve as the local delegate of the Portugal’s Central Government.

The population of Portugal is sprinkled unevenly across the eighteen districts. For instance, Lisbon is most thickly populated of all districts with approximately 2,250,533 residents. On the other hand, Portalegre is most thinly populated with approximately 118,506 residents. Even the land area allotted to these eighteen districts differs largely. For instance, with an approximate area of 10, 255 km², Beja holds the first rank in terms of land area. On the flip side, Viana do Castelo is ranked 18th with an approximate land area of 2,255 km².

The eighteen districts of Portugal are further subdivided into 4241 civil parishes and 305 municipalities. The municipalities have the responsibility of monitoring the municipal facilities as well as establishing the fundamental infrastructures. However, it is also anticipated that with time the municipalities will take up environmental protection and economic activities. On the other hand, the civil parishes handle day-to-day administration functions. Besides, they also take care of establishing and maintaining some infrastructures.