There are a few remains of medieval or early Christian structures in County Monaghan. One high cross, made up of two separate examples is to be seen in Clones. The absence of extensive occupation by Norman overlords in medieval County Monaghan partly accounts for the lack of Monastic remains. Warfare also had its effects, and the Franciscan Friary in Monaghan town was destroyed in the 16th and 17th centuries. There may be up to 40,000 individual sites in the Country, although many have been lost or are in poor condition.
Agricultural activity is the main cause of destruction.
Hill forts were defended farmsteads of early Christian to medieval date. After that time they continued to survive in use, but gradually declined. By the time of the English conquest in the 1600s, the ringforts were falling into ruin. Today, ringforts are recognised as hill-top features, having earthen banks and ditches, usually studded with trees and overgrown with grass and wild vegetation. Two particularly good examples are those at Lisaraw, near Monaghan town, and at Carrowhatta near Scotstown in the parish of Tydavnet.