County Roscommon is named after the county town of Roscommon. The Irish Ros means a wooded, gentle height and Comán was the first abbot and bishop of Roscommon who founded the first monastery there in 550 AD. The county is lowland drained by several rivers including the River Shannon. At the same time the underground is karstified limestone, so there is second drainage going on underground. The result are numerous karst lakes, which were called turlough in galic.