Fartullagh (Irish: Fir Thulach), previously Tyrrells country, is a barony in south–east County Westmeath, in the Republic of Ireland. It was formed by 1542. It is bordered by County Offaly to the south and three other baronies: Moycashel (to the west), Moyashel and Magheradernon (to the north) and Farbill (to the north–east).