Report on a dendrochronological study, conducted on samples taken of oak timbers from three of the moat bridges at Tattershall Castle. Tree-ring analysis indicated that all of the sampled timbers were of relatively modern date, being felled no earlier than the late 19th or early 20th centuries. It was therefore thought likely that the current bridges were all constructed as part of the restoration works undertaken by Lord Curzon, following his acquisition of the site in the early 1910s. Later dates from some of the sampled timbers indicate that the bridges were subject to several phases of repair works during the late 20th century. Samples were also taken from three ex situ timbers on public display in the basement of the castle tower. Only one of these samples could be successfully dated, however, giving a felling date of 1406-31. The original function and location of these timbers is not clearly known, although the felling date might suggest that this timber derived from the Cromwell ownership and re-building of the site.