Sewall’s Bridge, built to carry the Organig Road over the York River in York in 1761, is a very old wood-piling bridge. The pilings were of different lengths, the length of each determined by probing the river bottom with a long pole tipped with a pointed piece of iron. The piles were driven into the river bottom by standing them upright, then dropping heavy oak logs on them. The original bridge was so well built that it remained in use until 1934, when it was replaced with a wood pile bridge of a design very similar to that of the original. That replacement bridge is in regular use today. This bridge was dedicated as a historic civil engineering landmark on July 24, 1986.