West of Louisburgh, Co. Mayo, crossing the narrow Bunleemshough River, is the Bunlahinch Clapper Bridge. Of similar construction to bridges found in Devon and Cornwall, this clapper bridge, built for pedestrians, was made at a place on the river where the water depth was generally low. It is the largest complete clapper bridge in Ireland, 50m long. Its 37 arches are constructed in the primitive clapper style, each made of a clapper or flat limestone slab, about 0.6 m wide, resting on piers of about 0.6 m above the river bed. A clapper bridge is an ancient form of bridge. The design is prehistoric but most can be dated to the medieval period. The Bunlahinch Bridge probably dates to the 1840s when a Protestant Evangelist Colony, including a church and school, was set up beside the river.
The Colony, initially successful, went into decline and was abandoned after twenty years. The land was sold in 1878 and the church demolished in 1927.