"Slieve," the Anglicized form of sliabh, is the Irish word for mountain. Bloom thinks in Calypso of some hills that bear his name—"Mine. Slieve Bloom"—and a list of mountains near the end of Cyclops mentions "Slieve Aughty, Slieve Bernagh and Slieve Bloom."
The Slieve Bloom are an extensive collection of gently sloping, often forested hills, dotted with small villages, on the borders of County Laois and County Offaly in the center of Ireland. They are among the oldest mountains in Europe. Millennia of erosion have reduced their height from approximately 3,700 meters (12,000 feet) to a maximum of 527 meters (1729 feet).
The Slieve Aughty straddle the boundary of County Galway and County Clare, 40 or 50 miles due west of Slieve Bloom. They consist of two ridges separated by the Owendallaigh river. The highest peak is 400 meters (1,314 feet).
The much more rugged and bare Mourne mountains of County Down, Ulster include the peak known as Slieve Bernagh. Its rocky summit, the fourth highest in the range, stands at 727 meters (2,385 feet).