Rathcroghan

11mi/18km north of Roscommon, at Tulsk, where the N5 crosses the N61, are the remains of a castle and a Dominican friary. 3mi/5km northwest of this, at Rathcroghan, stretches an area of high ground some 2sq.mi/6sq.km in extent with a number of earthworks. The site (National Monument) is believed to have been the place of coronation of the kings of Connacht.

The earliest feature is a low mound, probably a passage grave. There are also various square, round, oval or irregularly shaped areas enclosed by earth walls. A standing stone within a stone ring-fort is said to mark the grave of Dathi, the last pagan King of Ireland. In the immediate vicinity are other ring-forts and megalithic tombs.