On the southern bank of the Tagus estuary, Barreiro is said to have been founded by fishermen from the Algarve, who established themselves here in the 15th century.
The town only acquired some significance in the middle of the 19th century, thanks to the construction of the first railway line south of the river Tagus, linking it to Setúbal; the beginning of the 20th century brought the first big factories to the county and Barreiro became an important industrial centre.
Barreiro is hardly a tourist zone, but the city's old nucleus offers visitors pleasant squares and some fine churches, such as the Miserichord Church, built in 1569 and displaying 18th-century panels of tiles.
Other churches worth visiting are the Mother Church of the Holy Cross, founded in the end of the 15th century and later rebuilt and remodelled for several times, and the impressive Church of Our Lady of the Rosary, from the end of the 18th century and exhibiting two bell-towers.
Other characteristic elements of the county's patrimony are the wind and tide mills (of the latter, there is one dating from the 15th century), which may be seen at several sites.
Visitors may also enjoy walks and leisure activities at the Machada National Wood, with diversified flora, at Alburrica, which includes a fluvial beach, and at Barreiro's two parks, besides different facilities and walks by the Tagus.
Local gastronomy is naturally influenced by the river and there are several typical dishes based on fish.