During the 6th century, a monastery flourished at this site. Ardcarn was designated as a diocese in the province of Connaught in 1111. It was later combined with Roscommon, Elphin and Drumcliff to make up the diocese of Elphin at the synod of Kells in 1152. This diocesan makeup of the area exists to the present day.
Ardcarn served as a market centre of the sheep and wool trade for many years.
The parish church remains, as well as the surrounding area, which contains earthworks and the last vestiges of what was once a thriving medieval village.