A togher is a timber trackway laid across wet or boggy ground, and the one at Cloonbreany is among the most substantial examples known in Ireland. Four metres wide and roughly half a metre deep, it was engineered to carry significant weight: the planks were laid transversely across large longitudinal runners, giving the whole structure the feel of a carefully considered piece of infrastructure rather than a temporary crossing.

The trackway was discovered in 1984 and runs in an east-south-east to west-north-west direction, connecting dry land to the east with an island of dry land further into the bog to the west. Dendrochronological dating, which establishes the age of timber by analysing its annual growth rings, placed its construction to 148 BC. That precision is striking; it means the people who felled the oak trees and laid this road can be located at a specific moment in the Iron Age, sometime during the middle of the second century before the common era. Several wooden artefacts were recovered in association with the structure, and the trackway bears close comparison to a second togher found nearby, apparently of a similar date.

Eighteen metres of the Cloonbreany togher have been conserved and are now on display at the Corlea Visitor Centre in County Longford, a building constructed deliberately along the exact axis of the original trackway in the bog. That alignment means that standing inside the centre, you are oriented precisely as the road itself once was, following the same line the Iron Age builders laid out across the wetland more than two thousand years ago.