Oeiras is a municipality in the western part of Lisbon metropolitan area, a subregion of Greater Lisbon, in continental Portugal. It is part of the urban agglomeration of Lisbon, 16 km from the capital. The population in 2011 was 172,120 living in an area of 45.88 km², making the municipality the fifth-most densely populated in Portugal.
Oeiras is an important economic hub, being one of the most highly developed municipalities of Portugal and Europe. It has the highest GDP per capita in the country, being also the second highest municipality in terms of purchasing power as well as the second one collecting taxes in the country. These economic indicators also reflect the education level of the inhabitants, as Oeiras is the municipality with the highest concentration of population with higher education in the country. It also has the lowest unemployment rate in the Lisbon area.