Rathcroghan (Irish: Ráth Cruachan, meaning "fort of Cruachan") is a complex of archaeological sites near Tulsk in County Roscommon, Ireland. It is identified as the site of Cruachan, the traditional capital of the Connachta, a term used to describe the prehistoric and early historic rulers of the western territory. The Rathcroghan Complex (Crúachan Aí) is a unique archaeological landscape with many references found in early Irish medieval manuscripts. (Wikipedia)