Tadcaster is a market town and civil parish in North Yorkshire, England, 15 miles north-east of Leeds and 10 miles south-west of York. Its historical importance from Roman times onward was largely as the lowest road crossing-point on the River Wharfe until the construction of the A64 Tadcaster by-pass some 660 yards to the south, in 1978. There are two rail crossings downstream of the town before the Wharfe joins the River Ouse near Cawood.