Lincoln CastleAt Lincoln, 16 miles north-east of Newark-on-Trent Built by William the Conqueror in 1068 on a Roman site. Added to over the years with the Bishop's palace a fine example of hall and chamber planning during the 13th century and later. Acted as the city's prison between 1787 and 1878. more information
Tattershall Castle8 miles south-west of Horncastle, off A153 Brick built castle constructed from 1434 by Ralph Cromwell, Lord Treasurer to Henry VI, replacing an earlier 13th century castle. After his death it passed to the Crown, then to the Earls of Lincoln, being bought by Lord Curzon in 1911 who restored it and bequeathed the castle to the National Trust. more information