Eolais Mac Biobhsach is the ancestor of the Muintir Eolais who were the most famous of the ancient Leitrim sub-septs of the Conmaicne territories of modern-day Leitrim (barony) and Mohill (barony). The primary sept of Eolais today are Reynolds, Mulvey, Shanley, and McGarry. From the 11th to 17th centuries, the ('tribe of Eolais') ruled most of the territory of present-day south county Leitrim. Place names preserve his memory. The townland of Corryolus () located in the town of Carrick on Shannon clearly retains his name. In the remote mountainous Cuilcagh-Anierin uplands, the oligotrophic lake named Lough Munter Eolas marks a borderline between west Cavan and south Leitrim.