a town of Portugal, in the province of Estremadura, and the corregimento of Alenquer. It is situated near the sea coast, on an inlet which forms a small lake called the Lago de Obidos, and contains 1090 houses, but not much more than 3500 inhabitants. On a hill adjoining are the ruins of an ancient castle. A battle was fought at this place by a part of the Duke of Wellington's army, previous to the conflict of Vimiera, in August 1808. It is about forty-five miles north of Lisbon.