Welland Viaduct, Harringworth Viaduct or Seaton Viaduct, crosses the valley of the River Welland

The viaduct is 1,275 yards (1.166 km) long and has 82 arches, each with a 40 feet (12 m) span. It is the longest masonry viaduct across a valley in the United Kingdom. Built by the contractor Lucas and Aird, a total of 30 million bricks were used in the viaduct's construction. Completed during 1878, it has since become a Grade II listed building.

The Welland Viaduct is on the Oakham to Kettering Line between Corby and Manton Junction, where it joins the Leicester to Peterborough line.