Ancient skeletal remains have been uncovered by contractors working on the largest energy project in the country.
The unrecorded burial ground was discovered on farmland in Rush, north Dublin, as EirGrid laid piping for a high voltage direct current (HVDC) underground power line.
Several skulls and bones were recovered on the strip of land near Rogerstown estuary, which locals historians believe could date back to the Vikings in the 9th century.
An on-site archaeologist has informed the National Monuments Service and is expected to be given the go-ahead to carry out a full archaeological survey next week.
It is not yet known how many bodies are buried there or exactly what era they date back to.
A spokeswoman for EirGrid said the section of land has been cordoned off and was being protected from heavy rainfall until examinations can be completed.
However work is continuing in the surrounding area.
"A previously unrecorded burial ground has been located on private land in Rush earlier this week," she said.
"It wasn't marked up on any ordnance survey maps."
She said there was no evidence of disturbance on the land before the 1.5 metres deep trench was dug on the farmland.