Possible remains of the the original Toodyay Road built by convicts have been uncovered during works undertaken by Main Roads.
A spokesperson from Main Roads said the works uncovered the hand-built structure.
"Layers of stone were uncovered, which would have been hand placed to form a layer called Macadam," the spokesperson said.
"This was an engineering technique developed by John McAdam of Scotland back in the 18th century.
"The macadam layer of angular rocks provides a strong platform upon which a pavement can be built on fairly weak existing natural ground."
The discovery following works to the road to remove material from an embankment to create wider pavement.
It is believed the paving made up part of the original route from Toodyay and Perth.
The spokesperson said while the work did uncover the stones, none were disturbed during the process.
"Upon the discovery Main Roads contacted the Shire of Toodyay, and the Department of Planning, Lands and Heritage, whereby we were referred to the Heritage and Properties Services team," the spokesperson said.
"Main Roads have also been in contact with the Shire's archaeologist."
The Department of Planning, Lands and Heritage said the road does not have to be referred for assessment under the Government Heritage Disposal Process and the stones will remain part of the road regardless of future works.
Shire of Toodyay president Brian Rayner said the historical discovery was a good find.
"They used to get convicts coming out to Toodyay who were on parole to work on the roads back in the old days," he said.
"We have a lot of convict history with links to Moondyne Joe and the old Newcastle Goal which is our museum."
Mr Rayner said the site will be further investigated.
