Linz, city in northern Austria, capital of Upper Austria Province, a major industrial centre and an important Danube port. Factories here produce iron and steel, chemicals, machinery, electrical appliances, and textiles. Urfahr, a formerly independent town on the north bank of the river, is now part of Linz. The Hauptplatz (the 13th-century main square dominated by Trinity Column, 1723), is in Old Linz, on the south bank of the river; other landmarks include a 17th-century cathedral (Alter Dom), where the composer Anton Bruckner was organist (1856-1868) and a 15th-century castle that is now a museum.

Linz dates from at least the 2nd century ad, when it was a Roman fortress settlement called Lentia. By the 15th century, it was a busy market town, famous for its fairs, and was for a time (1489-1493) the residence of the emperor Frederick III. Large iron and steel and chemical plants were built here after Germany occupied Austria in 1938. Population 188,362 (2006 estimate).