The Church of St Cronan, which serves the local Church of Ireland congregation, has foundations that archaeologists and historians date to the tenth century, making it a rare example of early medieval ecclesiastical fabric that has survived, in some form, into the present. Most early Irish churches of that period exist only as ruins or earthwork outlines; Tomgraney's has continued in active use across more than a millennium of religious and political change.

The site is associated with a monastery reputedly founded by St Cronan of Roscrea, and the church fabric retains elements that point to its pre-Norman origins, including stonework in the nave that is considered among the earliest surviving in Clare. The village itself sits within a landscape shaped by the Shannon and its lough, a corridor of movement and settlement since prehistoric times. By the medieval period, the area around Lough Derg was contested ground between Gaelic kingdoms, and small monastic churches like this one functioned as centres of local learning and pastoral life as much as places of worship.