(((Dave Walsh remarks: Here's a quote concerning methods of signalling in ancient Ireland, gleaned from the pages of Praeger.)))
"A little to the west of Westmeath lake region the hill of Usnagh or Uisneach rises gently to 250 feet above the surrounding undulating country, itself attaining some 600 feet above sea level. It has a rather extensive flattish top, which was a place of importance in old days, as witnessed by the number of monuments, mostly of the nature of ring forts and tumuli, which are scattered over it. According to ancient sources, it was the site of a royal palace and a royal cemetary in prehistoric times, and leading place of assembly; later, in early Christian days, it was the seat of the kings of Connaught.
"One point is worthy of note. Though of but small elevation, the Hill of Usnagh, standing in the middle of the Central Plain, commands a singularly extensive view. >From its summit, on a clear day, features belonging to no less than twenty out of the thirty-two Irish counties can be identified, and a beacon-fire lit here might be seen over one-fourth of Ireland, whence it could be readily relayed to the furthest corners. Probably this contributed materially to its early importance."
Dave Walsh (email@example.com)