The registered park overlies the remains of the medieval village of Horton, which lay to the south, south-east and east of the now demolished Horton Hall. The Royal Commission on the Historical Monuments of England survey of 1979, indicates an extensive settlement comprising roads, crofts and tofts south of the hall and a former pond (remodelled in the 1740s to create a landscape feature), ditched enclosures to the east and tracts of ridge and furrow cultivation across the park. Enclosure probably took place initially in 1584 when Robert Lane received licence to enclose a park with a fence and ditch taking in 200 acres (c83ha) of wood and 300 acres (125ha) of arable and pasture in the south of the parish and including Horton Woods. This park is not related to the registered landscape. To the south of the hall, the village appears to have been deserted by the early C17 and was cleared to the east in the early C18.
Formerly the property of the Parr family, in the mid-1620s, the manor passed into the possession of Sir Henry Montagu, created Earl of Manchester in 1626. An estate map of 1622 shows the Hall to have been surrounded by formal gardens at this date. Horton remained in the Montagu family until the late C18. The house was extended with a new wing by George Montagu, created Earl of Halifax (d.1739) in 1715. The Earl seems also to have been responsible for alterations to the gardens and pleasure grounds around the Hall. An illustration by Peter Tillemans in 1721 shows a formal parterre garden within a large walled court east of the Hall, which stood centrally across the court's west end. This garden was probably created when a wing was added to the hall in c1700. A broad, axial gravel walk ran down the centre of the court from the door to the wing with other walks around the edge of the court and crossing the centre. Running around the edge of the grass plots defined by the walks were clipped cones and globes in the Dutch style. Fruit was grown up the walls of the court. Earlier, in the early C17, there was an orchard and fishponds west of the hall, and a Cherry Yard lay on the south side of a canal located in the park to the south of the Hall, which was later remodelled to form serpentine lakes. Elements of the C17 gardens and pleasure grounds survived into the early C18, including the parterre, orchard and fishponds and the form of the Cherry Yard. In the 1720s, George Montagu, Earl of Halifax, landscaped the park, necessitating the removal of that part of the village remaining to the east of the Hall. An estate map of 1728 shows a triple avenue extending northwards. A second avenue, planted in a treble row near to the Hall then reduced to a double row, led south across the fields. Although still a prominent feature in the early C20, the avenue is no longer extant. Extending from the Hall's east court was a third avenue, which led across the site of the cleared village and over the adjoining fields. The avenue crossed a large pond which lay to the east of the village, a feature that was landscaped later to form an exactly circular pool, which survives as a distinct depression.
The second Earl (d.1772), George Montagu Dunk, after his marriage to an heiress, Anne Dunk, commissioned Daniel Garrett (d.1753) to encase the Hall and construct the eye-catchers, The New Temple and The Arches, on the north side of the park and, it is presumed, the Temple of Venus Cloacina (demolished in 1894) on the southern side, described by Sanderson Miller in his 1750 letter to Charles Lyttleton as 'paved with marble and wainscoted with mahogany'. In Miller's letter he further states that Garrett was at Horton in 1750, designing 'gothic bridges etc'. Thomas Wright, known as the Wizard of Durham, to whom payments were made by Halifax in 1754, 1756, and 1757 (Harris 1970), is said to have completed the design of the park and garden in the English Rococo fashion. In Wright's scheme, the north avenue of trees, shown on the estate map of 1728, was subsumed into a shrubbery: a wooded pleasure ground through which ran a serpentine drive along the northern boundary of the park to The New Temple. The stream which supplied the canals was dammed to form an upper and lower serpentine lake which snaked through the park, noted by Horace Walpole writing in 1763, as 'a fine piece of water'. At the east end of the lower lake, 500m to the south-east of the Hall site, the rusticated Green Bridge also served as a dam. Thought initially to have been the work of Garrett, it has been latterly suggested by Eileen Harris that it could be a piece by Wright, as the bridge was contrived so that the water would have flowed over a cascade built beneath it, a particularly Rococo feature. To the west of the bridge, in the mid C18, an ice-house was constructed in a ditched plantation, known as Icehouse Spinney, and, on the shore of the lake, a brick-arched boathouse with the remains of a rusticated fronting was built; both of these structures remain. The boathouse is presumably the feature shown in the c1760 view of Horton Park attributed to James Blackamore. On the south-east boundary of the park, the New Plantation was established. An artificial volcano, constructed on a raised mound was said to have featured beside the lake; its origin is uncertain and there is no documentary evidence to support its existence. The Green Bridge carried the drive leading to the Menagerie, designed by Thomas Wright in about 1750 (listed at Grade II*) on the south side of the park. Walpole, writing in 1763, makes mention of the feature describing it as 'a little wood, prettily disposed with many basons of gold fish'. Various wild creatures were kept here but the building also served as a dining room, sumptiously decorated, with kitchens beneath, apparently linked to the ice-house by a tunnel. It was restored from a derelict state in the mid-1970s by Gervase Jackson-Stops, the architectural historian, who lived there until his death in 1995. Jackson-Stops recreated a smaller scale version of a Wright-designed garden for Badminton here in the C20, in addition to a lavish shell-grotto.
The New Temple was converted to housing and extended in the late C19 and The Arches was turned into a dwelling in the early C20. After the demolition of the hall in 1936, the gardens and pleasure grounds were covered by lawn and late-C20 development including housing. The park, however, remains mostly as permanent pasture with some of its C18 features, including five listed buildings, the archaeological earthworks of the village and associated features. The upper lake has been drained since the 1920s; the lower lake is greatly silted up and neither the cascade nor the putative volcano can be clearly discerned.