TUY (the ancient Ludal ad Fines), a fortified town of Spain, Galicia, province and 28 miles S. of Pontevedra, on the right bank of the Minho, which here forms the Portuguese boundary, and about 18 miles from its mouth in the Atlantic. The town occupies a height, and is regularly laid out and clean. It has a cathedral, town-hall, prison, barracks, and manufactures of table-linen, leather and hats. The vicinity is highly fertile; but the climate is unhealthy from marshes, and the town is decaying. Pop. about 5000.