The Municipality of Estarreja, belongs administratively to the Aveiro district (Beira Litoral), is located in the Baixo Vouga sub-region and is part of a regional individuality - the Ria; it is characterized by the existence of mats and canals in all parishes, this marine influence constitutes in it and around it, a diversity of biotopes (free waters, islands with vegetation, vases and muds, marshes, salt pans and agricultural fields), with great importance from an ecological point of view.
The entire county is very cut by water lines, the most important being the Antuã River, characterized by well-protected margins where slopes of more than 25% are recorded at the same time, giving the landscape a surprising and bucolic charm, through the dams and watermills along its course.
Due to its geographical situation it is part of the range of temperate climates (T.M.A. - 14ºC) of Mediterranean influence. It is limited by the municipalities of Ovar, Oliveira de Azeméis, Albergaria-a-Velha and Murtosa, being served by an important road network.
With traces of prehistoric settlement, the municipality of Estarreja dates back to 1835. The Foral da Vila de Antuã was granted on November 15, 1519 by D. Manuel II. Estarreja was elevated to City on January 26, 2005.
Holder of a unique natural heritage, Estarreja has more than 20 km of riverfront sprinkled and cut by Esteiros and Ribeiras. The municipality's natural mysteries can be discovered in the nature trails of the BioRia project.