a town of Portugal, capital of a district of the same name, in the province of Estremadura, on a rocky hill on the right bank of the Tagus, 50 miles N.N.E. of Lisbon. It is in general well built, although many of its splendid mansions are in a ruinous condition. Some remains still exist of the ancient walls, which in the time of the Moors gave the place such strength, that it was considered almost impregnable. The town is remarkable for the number and antiquity of its ecclesiastical buildings. One edifice, originally a mosque, and thereafter a church, is now used as a theatre, and much defaced. Besides churches and convents, the town contains also schools and hospitals. The surrounding country is very rich, and Santarem carries on an active trade with Lisbon by means of the river, especially in corn, wine, and oil. Pop. 8000.