The Hill of Dunnideer is a conical height of 265 metres, overlooking the small Aberdeenshire town of Insch from the west. It is made more prominent by the ruins of a 13th century tower house on the summit, and also was the site of an iron-age hillfort.
A small cap parking area lies at the foot of the hill's eastern flank on Western Road, and a stone-built plinth carries historical information on the hill, right at the start of the path that leads to the summit. The text reads as follows:
'On the hill of Dunnideer, many phases of fortified settlement can be seen ranging in date from the iron-age through to the Medieval period.
The most obvious remains are of a 13th century castle, now ruined, which crowns the summit of the hill. This castle, built around 1260AD, is amongst the earliest surviving tower houses in Scotland. According to local tradition, a castle is said to have been built at this site around 890AD by Gregory the Great (Giric, a Pictish nobleman). Others have suggested that a castle was built here in 1178AD by David, Earl of Huntingdon and Garioch. However, the first written reference to a castle at Dunnideer is in a document dated 1260AD. In it, Sir Josceline de Balliol, "Lord of Dunnideer", grants access to his land to the Abbey of Lindores with the condition that "the Abbot should pay to Sir Josceline and his heirs a pair of white kid gloves every Whitsunday at his Castle of Dunnideer."(W.D. Simpson, Earldom of Mar 1949)
The castle is a simple rectangular tower with two narrow-slit windows in the basement. The west gable is pierced by a lancet window, now damaged, and stands to a height of 9 metres. The castle is built largely from stone removed from the earlier fortifications which enclose the hilltop.
On the summit surrounding the castle, two lines of defence from an earlier hillfort can be seen. The outer line, (B on plan) is a low stony bank, best seen on the north and east sides. The inner line (A) encloses an area of around 65 x 27 metres and includes a vitrified stone wall. Vitrified stone has a "glassy" appearance, the result of the stone having been exposed to some really high temperatures. Here, this was caused by the burning of the timber framework within the wall. The void, where the timber once was, is still visible in one area.
Three other lines of defence survive on the lower slopes in the form of earth ramparts now visible as low banks. The clearest is the central line (D), while the inner (C) and outer (E) lines are less distinct. The remains seem to show at least two main structural phases, but there is no evidence to indicate if the vitrified fort was built before or after these outer defences.
In 2008, as part of the Hillforts of Strathdon Project, a small trench was excavated on the south east corner of the inner summit defence line. This showed that the rampart had been levelled during the medieval period. Two charcoal samples were radiocarbon (C14) dated which indicate a date for the vitrification of between 550 and 250BC.'
The sign also includes an ariel photograph of the hill, and an illustrated plan of the hillfort.