Dunwan Hill is believed to be the site of an ancient hill-fort - learn more about it here
Hill-forts and enclosed settlements are particularly associated with the Iron Age (800 BC - AD 43), although its likely good defensive positions pre date this time, possibly to the bronze age or Neolithic times.
Dunwan Hill (found at NS547489), is a prominent steep sided, flat topped hill within the windfarm that appears ideal for, and is believed to have been used as, a defensive position. The Royal Commission On The Ancient and Historical Monuments of Scotland (RCAHMS), recorded a hill-fort or fortified dwelling dating from around the iron age. Surveyed in 1963 the Dunwan hill-fort is said to have been constructed with 12 feet thick earth mound walls or ramparts around the top of the hill. Within this are several hundred meters square of ground in which it is thought were found 2 circular timber buildings. (Circular depressions on the ground that are now filled with rush indicate the locations of these buildings on the ground still.) Around the base of the hill were further earthen fortifications and a well for water was said to be located on one of the slopes and within the earthen walls, allowing the inhabitants access to water if there was siege. Some authors have suggested that hill-forts were less about defence and more about status - the prestige of holding and living within a fortified settlement. Fortified settlements were not built everywhere in Scotland however, perhaps indicating they weren't needed everywhere. There are also suggestions that hill-fort locations were possibly ceremonial sites or meeting points.
Please follow the link in the External websites section to the RCAHMS website where further information on the site can be found, including a plan of the hill-fort enclosure.
Another hill-fort at Duncarnock near Nielston does show that they were a popular feature in the Whitelee/East Renfrewshire area. A piece of broken roman pottery found at this hill-fort indicates the continued use of such prominent and easily defended hill tops through the ages and it is likely that the romans*, and other invaders and defenders, will have used these sites through history.
(* A roman coin was found in a garden in Eaglesham and in the 1970's, 2 archaeologists said they had found the remains of a roman road at Myres Hill, again within the windfarm - but this was never found again or verified.)
During the construction of the windfarm a number of archaeological digs were carried out at sites of interest including old roads, turf banks and turf bank walls thought to be remnants of old turf walled dwellings. No archaeological artefacts were recovered however.