AlegsaOnline.com County Offaly Author: Leandro Alegsa 13-11-2022 County Offaly (Irish: Contae Uíbh Fhailí) is a county of Ireland. County Offaly is in the province of Leinster. It is named after the old kingdom of Uí Failghe. The population of County Offaly is 76,687 as of 2011.