A wind farm developer has paid for archaeologists to scan a cluster of seven Neolithic horned cairns near to where 21 turbines will be erected.
The 5,000 year old structures at Hill of Shebster, near Thurso, in Caithness, were used for burials and rituals.
Light Detection and Ranging (LiDAR) equipment was used to map the cairns.
Edinburgh-based AOC Archaeology also recorded 300 new Bronze and Iron Age sites in the £100,000 project funded by Baillie Wind Farm.
The new sites included hut circle settlements.
Archaeologists have produced three-dimensional images of the horned cairns from the scans.
The stone structures are more than 60m (196ft) in length and have two projecting walls at their entrances that create small courtyard areas.
A car park and path are to be built near the cairns to allow the public to visit them.
Consultant Dr Graeme Cavers, of AOC Archaeology, said: "The Shebster area is an unusually good example of a well-preserved cluster of sites.
"They are essentially burial and ritual monuments, much like the chapels and shrines of more recent times, and each of them is likely to have been used exclusively by individual local groups or communities."
He added: "The survey makes an invaluable contribution to the archaeological record of Caithness, and is really the first large-scale survey of its kind undertaken in Scotland."
Caithness is rich in ancient sites.
It has more examples of massive stone wall roundhouses, known as brochs, per square mile than any other part of Scotland, according to Highland Council.
The remains of a broch at Nybster have been dated to 700 to 500 BC, but archaeologists believe the site may have been occupied long before the Iron Age and also for many years after, including up to medieval times.
The Duke of Rothesay toured an archaeological dig at the site in August 2011.
Prince Charles was staying at Castle of Mey, the late Queen Mother's summer residence in Caithness, at the time.
Finds from the more recent past have also been made in Caithness this year.