Early 19th century milestone to the east of the junction with the A1 at Colsterworth. It is triangular in plan, and is made of cast-iron with a limestone back. The facetted and chamfered metal plate is inscribed 'COLSTERWORTH' in the top panel, with 'BOURNE 12' and 'COLSTERWORTH 1/2' in the respective side panels. For the full description of this listed building please refer to the National Heritage List for England. {1}{2}