Work to develop the site of a new prison in Inverness has uncovered a “truly important” 2,000 year-old prehistoric settlement, archaeologists have announced.

Working alongside contractors building HMP Highland, the archaeologists found evidence of 16 roundhouses on the site, surviving as circular groups of holes where the timber posts holding up the structures would once have stood.

The excavations, which were carried out between June and November 2022, also uncovered hearth and cooking pits, midden pits, enclosure ditches, and other timber shelters.

The team from the AOC Archaeology Group also found a variety of prehistoric artefacts on the site, including iron and copper-alloy objects, stone tools like whetstones and querns (hand mills), pottery and worked flint.

Debris from iron-working was also spread over the entire site, with clay moulds and copper-alloy material in some areas indicating that specialised objects may have been cast there as many as 3,000 years ago.

One mould was for a Bronze Age leaf-shaped sword, which the archaeologists say is a rare find in northern Scottish contexts.

Mary Peteranna of AOC said: “An excavation like this is a real team effort. We worked closely with the contractors to ensure construction progressed while the archaeologists worked.

“The collaboration was made possible by the support of the Scottish Prison Service (SPS). They facilitated the process of safeguarding the archaeology on the site and have been fully supportive of presentation of the results so that it is available for the public.

“This is a truly important part of the cultural heritage of Inverness.”

The prehistoric settlement forms part of a larger archaeological landscape in the area, which contains evidence of activity spanning several millennia, and where nationally significant archaeological material has been found.

Much of this has been uncovered over the past two decades through archaeological work linked to new developments.

This includes at the sites of University of the Highlands and Islands campus, housing developments like Culduthel and Slackbuie, the West Link Road and the golf course at Torvean.

Lorraine Roughan, SPS project executive for HMP Highland, said: “We were delighted to hear of the significant archaeological discovery made by the team from AOC Archaeology Group at the site of the new HMP Highland.

“This discovery encapsulates the importance of the site to the community of Inverness, both historically and in the present day.

“The construction of HMP Highland has so far seen the creation of new jobs and apprenticeships for the local area, and we look forward to maintaining this community focus with more to come in future.

“HMP Highland will allow us to better serve local communities, meet the needs of people in our care, and support our staff.

“Enhanced security, greater digital capability, modern living spaces, and a new community connections hub with an improved visits area will enhance dignity and decency for all.”

HMP Highland, being built on Eastfield Way in Inverness, is due to be completed in 2026 at a cost of £209 million.

Once built it will be able to accommodate 200 prisoners, which is over 100 more than the design capacity of Inverness Prison, which it is replacing.