Sleaford's Castle grounds are a popular area of public open space and now the subject of a major research project coordinated by the Sleaford Castle Heritage Group. Archaeological and historical research is expected to continue for several years.

Sleaford Castle was built by the Bishop of Lincoln, Alexander de Blois between 1123 and 1139 and held by the Church for over 400 years. The castle fell out of use in the mid-1500's and into disrepair. It was substantially demolished in the following century. Little remains to be seen today apart from earthworks and a small remnant of a tower in the north-eastern corner of the riverside castle site.

The Sleaford Castle Heritage Group is an advisory committee of the Council comprised of Sleaford Town Councillors and representatives from the Sleaford & District Civic Trust and other bodies.

The group advises the Council on a major project to bring Sleaford Castle into the public's view, improve accessibility and present the history of this interesting Norman Castle. The Group endeavours to learn as much as they can about the Castle's construction and its place in Sleaford's history.

An educational project, including a limited geophysical survey, was completed in 1993. There was also a successful project conducted in about 2018 on the Castle by pupils in years 7/8 at Carre's Grammar School and in June 2019, sixth form students participated in a limited geophysical survey of the site using resistivity techniques. The results from the survey encouraged the Group to undertake a full ground penetrating radar survey.

Archaeological digs took place at the site in 2023 and the report on findings of them can be found below.