These are toghers, a word from the Irish tóchar, referring to causeways or trackways laid across bogland to allow passage through otherwise impassable ground. The concentration of them at Cooleeny is remarkable, and what survives gives a detailed picture of how Iron Age communities engineered their way through the wetlands that dominated the Irish midland landscape.

A field survey carried out by Gowen in 1999 documented the full extent of the Cooleeny toghers, identifying variations in construction method across the group. Most were built using a combination of brushwood and roundwood timbers laid together, though six relied on roundwood alone, eight on brushwood alone, and one unusual example incorporated brushwood and gravel. Radiocarbon dating was obtained from two of the toghers, and both returned Iron Age dates: one ranging from 388 to 207 BC, the other from 372 to 192 BC. Wood species analysis, carried out on seventeen of the toghers, revealed that the builders were drawing on whatever the local landscape offered, including alder, ash, birch, blackthorn, hazel, mountain ash, and willow. The diversity of species suggests a practical, opportunistic approach to construction rather than any strict preference, with different toghers likely built at different times or by different hands. Taken together, the Cooleeny group offers an unusually dense record of how Iron Age people moved through and made use of boggy terrain that would otherwise have separated communities and impeded travel, trade, and everyday life.