Thornborough Bridge (That Part in Buckingham Civil Parish)

Thornborough Bridge, located in Buckingham Civil Parish, is a bridge dating from the 15th century, with repairs and alterations made in 1661, along with additional late 19th and 20th-century repairs. It is constructed of coursed squared limestone, featuring some ironstone, particularly in the lower courses, and has limestone dressings. The bridge also includes blue brick and cement repairs at the bases of the piers.

The structure consists of six 4-centred arches. The arch to the east of the center is hollow-chamfered, while the one to the west of the center is double hollow-chamfered. Both arches are divided into three bays over channels by two hollow-chamfered ribs and have hoodmoulds on the south side. The penultimate arches are chamfered with hoodmoulds, and one label stop on the north side at the west end features a male head with a mason's cap. The outer arches are also chamfered and set at a distance from the others.

There are three central piers that have cutwaters on the upstream (south) side, which extend through the parapet to create passing places. The penultimate pier at the west end has a rectangular projection on the north side, which includes a passing place and an inscription panel on the north face. This panel reads: "THIS BRIDG WAS REPAIRED AT THE CHARGE OF THE/ COUNTY: ANO DOMINYI 166(1) ACCORDING TO ASESIONS/ ORDER: SR. RICHARD TEMPL(E) SR. TOBY TUREL BARRONETS/ AND THOMAS STAFFORD ESQUIR BEING APPOYNTED/ TO TAKE ORDER FOR THE DOING OF (T)HE SAME/ AND WILLIAM WOOLLHEA(D) OF THORNBOROW YEAMAN WAS/ TU....ER OF THE SAID WORK THOMAS N..O... THE SAYE." The inscription is damaged and fractured in places, with reversed Ns, and is flanked by raised shields. The left shield reads: "THOMAS/ WARD M/ ASUN," and the right shield reads: "ROBERT/ COLLISON(?)/ MAS(ON)." There is a string course below the inscription, and a mason's name, "JOHN CARR," is inscribed on the left side of the pier lower down in similar script. The initials R and reversed W appear in other locations. The bridge features irregular 20th-century stone coping.

Approximately half of the bridge is situated in Thornborough Civil Parish, spanning the Claydon Brook, not far upstream from where it joins the River Ouse. It is also designated as a Scheduled Ancient Monument.