Tagus
the largest river in the Span-1 ish peninsula, which, rising between the Sierra de Albarracin and the Sierra Molina, on the frontier of Aragon and New Castile, flows S.; then, holding a W. course through the rest of Spain, enters Portugal, when, pursuing a more S. direction, it passes Lisbon, forming the magnificent harbor of that city, and, spreading into a splendid estuary, finally mingles its waters with the Atlantic after a course of 625 miles. Above the capital of Portugal it has a width of 5 miles; at the city a breadth of 2 miles; but, in consequence of its deep banks and impetuous current, the Tagus is but little adapted to mercantile purposes and is at present only navigable to Abrantes.