LOUGH

DERG  , a lake of Ireland, on the boundary of the counties Galway, Clare and Tipperary . It is an expansion of the Shannon, being the lowest lake on that river, and is 23 m. long and generally from 1 to 3 M. broad . It lies where the Shannon leaves the central plain of Ireland and flows between the hills which border the plain . While the northerly shores of the lake, therefore, are flat, the southern are steep and picturesque, being backed by the Slieve Aughty, Slieve Bernagh and Arra Mountains . Ruined churches and fortresses are numerous on the eastern shore, and on Iniscaltra Island are a round tower and remains of five churches . Another LOUGH DERG, near Pettigo in Donegal, though small, is famous as the traditional scene of St Patrick's purgatory . In the middle ages its pilgrimages had a European reputation, and they are still observed annually by many of the Irish from June r to August 15 . The hospice, chapels, &c., are on Station Island, and there is a ruined monastery on Saints' Island .