Lisbon is the capital of Portugal.
Lisbon ( [ ˈlɪzbən ] Lisboa , [ liʒˈβoɐ ] ) is the capital and the largest city of Portugal , with a population of 552,700 within its administrative limits in an area of 100.05 km ² . Humberto Delgado Airport serves over 20 million passengers annually , as of 2015 , and the motorway network and the high-speed rail system of Alfa Pendular link the main cities of Portugal . Lisbon Humberto Delgado Airport , also known as Lisbon Airport or Portela Airport , is an international airport located in the city of Lisbon , the capital of Portugal .