The earliest reference yet found is in a grant by Robert Hilton in 1323 referring, among other things, to the freemen and cotmen of Hilton. In 1347/ 8 the vill of Hilton owed tithes to the church of Monkwearmouth, and there must be many, and much earlier, references of this sort. The vill occurs in C15 grants, e.g. Sir Robert Hilton granted the prior and convent of Durham a place in the vill on which to build a tithe barn, but in 1820 Surtees wrote "There is no village". Fryer's map of 1800 shows buildings on the E side of the S end of Hylton Lane, and perhaps a farm on the S side of the road from Southwick. Field names here, e.g. Town-end field. Present knowledge therefore suggests this as a possible site, - there is no other obvious one. The 1st edition Ordnance Survey map refers to this area as West Town Moor and shows a farm comprising of three ranges around a yard and a horse gin. There is a second farm immediately to the north-east called North Town Moor. By 1896 North Town Moor had gone and a gravel pit had been excavated to the north-east. West Town Moor farm was demolished in 2003.

Earliest known reference is 1157, when Romanus of Hylton obtained permission to appoint a chaplain for his chapel. The Hyltons were later allowed to bury there, leading to the foundation of chantries, and there were 3 chantry priests by 1370. The last recorded chaplain was 1536. Thereafter there were only occasional attempts to keep it in repair, - 18th century and early C19. Roofless, the chapel now consists of a chancel, rebuilt in the early C15, and altered in the late C15/early C16 by the insertion of some windows, blocking of others, and external refacing, and in the mid/late C16 by the addition of two two-storey "transepts". The chapel once had a nave, which was perhaps added at the same time as the "transepts", and demolished in the 18th century when the chancel arch was blocked except for a new door and window.

"A fine gatehouse tower resplendent with a magnificent display of heraldry and with extravagant battlement works". Built by Sir William Hylton in late C14/early C15. Basically rectangular in plan, with octagonal turrets on W buttresses and angles, a broader E turret, bartisans on E angles, machicolations and figures on the merlons, it was 4 storeys high. Central through passage, 2 vaulted rooms on each side, on ground floor. Stair in E turret led to first floor with central hall, which rose to roof, and was flanked at high (N) end by the principal chamber etc., at low end by kitchen etc. Other rooms above, chapel in E turret. Gutted by John Hylton (d. 1712), converted into 3 storeys, given N wing. His son John added S wing, Neo-Gothick porch etc. The castle left the Hyltons in 1746, was later bought by Mrs Bowes, was rescued by Simon Temple in 1812, and in 1863 bought by William Briggs, a Sunderland merchant, and converted yet again. Threatened with demolition, it was taken into guardianship in c. 1950.
A watching brief was undertaken by TWMS in December 1989 to the west of the castle during the construction of a custodian's office with no significant result. In December 1993 a detailed study of Hylton Castle was compiled by TWMS. In June 1994 archaeological work was undertaken by the "Time Team" television programme. Geophysical survey of the grassed areas to the east of the castle revealed another complex of buildings. Excavation showed the building closest to the castle to be a probable medieval feasting hall contemporary with the gatehouse, the other further to the east, a large Elizabethan house. Ploughed out ridge and furrow was identified by the survey to the south-west and an ornamental pond. Raised gardens or a cobbled surface was identified to the west of the castle.
In July 1994 TWMS produced the "Hylton Castle Historic Gardens Project, Research and Restoration Design" report. In November 1994, trial trenching at Cranberry Road west of Hylton Dene revealed no archaeological deposits, although fieldwalking indicated ridge and furrow. A watching brief in November 1994 during the insertion of an interceptor sewer south of the Dene revealed no archaeology. In July 1995 four trenches were excavated south of the castle in advance of the construction of a playground. Two metalled tracks were identified - probably of C19 date and part of the ornamental gardens.
In 1995 TWMS compiled an Earthwork and Documentary Survey of Hylton Castle gardens. This concluded that the easternmost range and terraced garden were post medieval in date. The building was probably never finished as traces of it was sealed beneath C18 and C19 gardens. In November 1995 five evaluation trenches were excavated in advance of the construction of pathways around the castle. The north wall of the north wing of the C18 extension was located along with a brick-lined drain, cobble surface, four pits and the base of a sandstone column. In 1998 Steve Speak and Beric Morley prepared a summary report of recent work at Hylton Castle.
Local residents formed the Friends of Hylton Dene group in 1999 following the interest generated by "Time Team". The gardens and dene have been restored by City of Sunderland and Durham Wildlife Trust. The Friends Group have published a new information leaflet and secured LHI funding to hold an event to raise awareness of their local heritage in May 2003. They funded the completion of an archaeological assessment of the footprint of a proposed new visitor centre and the subsequent excavation of two trial trenches. The trenches failed to find any medieval deposits. They did demonstrate however, that the earthen bank to the south of the gatehouse is manmade and is built of C18 rubble, probably from the north and south wings which were demolished in the 1860s. For more information see www.hyltoncastle.com.
A Heritage Statement by NAA in 2015 identified Hylton Castle as being of exceptional evidential, historic and aesthetic significance. An evaluation in 2015 by NAA found that the foundations of the castle consisted of roughly hewn limestone, with an overall depth of 0.60m. A test pit located within the interior courtyard showed evidence of wall foundations and the possible remains of a dismantled flagstone floor surface, held in a substantial mortar foundation layer. The larger area of excavation largely comprised a rammed earth floor, possibly the bedding for a flagstone surface. This had been cut by later 19th or 12th century interventions. The standing features surviving of some significance comprised the medieval cross-wall and a cobbled surface at the northern end of the quadrant. The date of the latter has not been established but archaeological deposits could be preserved beneath. It is recommended that these features, alongside the other standing features within the castle interior, are preserved in-situ.
In terms of sub-surface archaeological deposits, preservation was found to be poor, indicating that much material had already been lost when the building interior was cleared in the late 20th century. What does survive appears to have been extensively disturbed by a number of intrusive features, likely to be of mid to late 19th century in date. As such, nothing observed during the evaluation would indicate that the archaeological deposits are of such significance to severely limit development or require preservation in-situ. However, some important information was still gleaned from the surviving evidence and it is recommended that archaeological excavation be undertaken across the whole interior of the castle prior to any development work.
The investigation of the basement entrance revealed a flight of steps bordered by two retaining walls leading down to a walled up doorway. This entrance had been sealed during the 1980s or earlier. Upon mechanical removal of part of the door blocking, it was possible to enter the basement and a detailed survey was carried out. This demonstrated that the basement consisted of a series of room linked by a central passageway.
Excavation in the interior of the castle in 2016 by NAA revealed evidence of an early phase of occupation – pre-dating the construction of the gatehouse in the late 14th century. Evidence of this is indicated by a series of foundation cuts through established floor surfaces. These relate to the primary gatehouse walls including the east wall and north wall of the building as well as the internal cross walls. In the south-east chamber a series of post holes were identified, possibly associated with a single structure. In the north-east chamber, a stone feature was observed preserved beneath a concreted cobbled surface. This is believed to be the remains of the entrance to the northern garderobe. Prior to the excavation, no evidence of the garderobe survived above ground, calling into question its existence, despite two late 19th century architectural accounts of the feature.

"A human lower jaw and fragments of long bones and pelvis found 1965 by A. Chalk of 17 Fortrose Avenue and D. Holland". Though apparently noted in the Sunderland Museum records, there is no further information. Miket suggested they may have been prehistoric.

Fragments of human skull (male) were found during deep excavation for building purposes at Laing's (or Doxford's) Shipyard, Deptford, in 1974. Donated to Sunderland Museum.

Miket reports that one arrowhead, lacking its tang, was found in 1950, and three were found c. 1953. Young received this information as "3 leaf-shaped arrowheads...recovered from the area of Humbledon Hill in the 1950s", but added, cryptically: "this material was not traced at Sunderland Museum".

In 1873, during the construction of the Humbledon Hill High Reservoir on the summit of the hill, a barrow was removed and three urns were discovered. 1) A food vessel urn was found about 4 ft below the surface, about half full of small bones. 2) A second urn was found about 3 ft below the surface, 9 ft east of no. 1, with some bones in it, "but it fell all to pieces before it was got out". 3) A food vessel urn, crushed before it was recovered. A small heap of bones, without a cover, was also found, 3 ft below the surface. Nos. 1 and 3 are recorded as having been found inverted, and the implication is that no. 3 also held a cremation.

"A discovery...was made several years ago. In working the lime-stone quarries, [on Fulwell hills], 'a kind of square pit was opened,...within which were deposited, a quantity of stags' horns cut into lengths of three or four inches, and resting amongst a deep-coloured substance most resembling animal matter".

Toffee-coloured flint scraper found in Sunderland in 1973, and donated to Sunderland Museum by F. Hare, 31 Hadleigh Road, Hylton Lane, Sunderland.

Small Neolithic axe, in Langdale volcanic tuff; length 82 mm, width 57 mm, thickness 24 mm. Found in 1972 "near the path that runs from Mill Garages to Fulwell Quarries". Donated to Sunderland Museum.