The county was part of the central plain of Ireland, but the diversified terrain contained several mountain ranges: the Arra Hills, Silvermine Mountains and the Devil's Bit. The county was landlocked. The southern part of the former county is drained by the River Suir; the northern part is drained by tributaries of the River Shannon which widens into Lough Derg. The centre of the county included much of the Golden Vale, a rich pastoral stretch of land in the Suir basin which extends into counties Limerick and Cork.