There are several fine estate plans kept at the Castle including the 1746 plan by Winter, the 1764 design plan, the 1768 plans by Abercrombie and the 1810 map by Blackadder.
The original stronghold was built in the 10th or 11th century, and was added to in the 16th, 17th and 18th centuries. Prior to 1372 the estate was used as a Royal Hunting Lodge but was granted in that year by Robert II to John Lyon who had married the King's daughter, Dame Joanna. Their grandson, Patrick, was created Lord Glamis in 1445. The 6th Laird, John, married Janet Douglas who was burned at Edinburgh on a trumped-up charge of conspiring against James V. James V lived at Glamis for some four years after this and left the Castle impoverished on his departure. The estates were recovered by the 7th Laird in 1543 and were handed down through the family to the 9th Laird, Patrick, created 1st Earl of Kinghorne in 1606. He started work on the modernisation of the Castle but it was left to his grandson Patrick, the 3rd Earl, who succeeded in 1646, to complete the improvements. It is not known whether the final design was that of Inigo Jones or not.
When the 3rd Earl succeeded, it was to an enormous debt of #400,000 and to a Castle which was uninhabitable. He not only repaired the family fortunes, but improved the grounds and modernised the Castle. The 3rd Earl's garden is reputed to be one of the great four Baroque gardens in Scotland. In 1688 the 3rd Earl obtained a charter for the titles of Earl of Strathmore and Kinghorne, Viscount Lyon, and Baron Glamis.
The 4th Earl, John, had four sons who all succeeded to the earldom in turn, and in fairly rapid succession. In 1735 the 8th Earl, Thomas, the last of his sons, succeeded and commissioned Thomas Winter to produce the 'Plan of the Mains of Glamis containing all the Parks, and Meadows and Plantations, Courts and Gardens as presently laid out'; apart from the woodlands and avenue described above, this plan also shows a formal garden layout to the north of the Castle and up to the river. Winter added to his plan a revised formal design for the courts and north garden, and he also put in a beech avenue. Roy's plan of 1750 shows the layout as substantially the same as the more detailed Winter survey. The 8th Earl died in 1753 and was succeeded by his son John as 9th Earl. John married an heiress, Mary Eleanor Bowes, and the family name was changed to Bowes Lyon. Around 1764, the 9th Earl consulted Robert Robinson about draining the Forfar Loch (to the east of Glamis near
Forfar town), and Robinson is reported to have visited Glamis in 1764. An improvement plan for the estate in the picturesque style was drawn up in that year. It is untitled, unsigned and unfinished and has been attributed to Robinson as containing his theories of landscape design. However, the style, script and artwork are similar to that of Thomas White Snr, in which case it would be one of his earliest known works in Scotland.
The plan was not carried out and the 9th Earl later commissioned James Abercrombie to work on the estate from 1766-1771, initially as a surveyor, and for agricultural improvements such as draining and planting. Abercrombie apparently worked well with the gardener of this time, George Baillie, and a shrubbery was put in near the house. Abercrombie also drew up two proposals for the improvement of the policies in an informal style in 1768, at the same time making a plea for the gates and walls to be retained in the front of the Castle. His plans show a picturesque design on the same lines as the 1764 plan with the removal of all the formal areas of planting including the avenue, and with the construction of two connected lochs to the south of the Castle. A kitchen garden is shown north of the Castle, and there is evidence from later survey plans to show that some of these proposals were implemented. However, Abercrombie's plans to save the court walls failed and these were demolished in 1774. The gates however were saved and moved to the perimeter of the policies to form the gate lodges in the policy wall. Of the three gateways shown in the late 17th century portrait of the 3rd Earl, the outer gates were moved to the south-east entrance or Church Lodge, the middle or De'il Gates were moved to the South Lodge, and the inner, Gladiator Gates, to the North Lodge.
The main approach avenue, described by Winter as an approach of 'ten hundred feet wide and a strip of planting of the same breadth on either side', was also cut down at this time. The poet Thomas Gray had described it in 1765: 'You descend to the Castle gradually from the south, through a double and triple avenue of Scotch Firs, 60 or 70 feet high, under three gateways. This approach is a full mile long, and when you have passed the second gate, the firs change to limes, and another oblique avenue goes off on either hand towards the offices; these as well as all the enclosures that surround the house, are bordered with three or four ranks of sycamore, ashes, and white poplars of the noblest height, and from 70 to 100 years old. Other alleys there are that go off at right angles with long ones, small groves and walled gardens of Earl Patrick's planting, full of broad-leaved elms, oak, birch, black cherry trees, laburnums, etc, all of great stature and size,' and its loss was mourned by Walter Scott, among others. The 2,700 acre parks were informalised, and the offices removed from their site adjacent to the doocot, which was left as a feature in the park.
The 9th Earl died in 1776, and was succeeded by his son John, 10th Earl, who commissioned the surveyor Blackadder to draw up a plan of the estate in 1810. This shows the park without its central avenue and with a rectangular pond to the east of the House. However the avenue must have been replanted shortly after this plan was drawn up as the present trees date from this period, and it is shown as mature by the 1860 1st edition OS map of the estate. The 10th and 11th Earls were both renowned agricultural improvers, enclosing all the farms on the estate, draining, fencing, building, reclaiming land and making roads. Many of the farm buildings date from this period. In 1865 the 13th Earl, Claude, succeeded, and Fowler of Castle Kennedy was brought in to design the five acre walled garden to the north of the Castle. The Pinetum was planted by the 13th Earl in the shrubbery to the north of the Castle, and in 1891 a new formal Dutch garden was put in to the south of the Castle.
The area of formal garden was extended in 1907 with the creation of the Autumn Garden to the east of the Castle by Cecilia, the 14th Countess, mother of H.M. Queen Elizabeth the Queen Mother, who spent her childhood at Glamis. The 14th Earl died in 1944 and his grandson Fergus is the present and 17th Earl.