[1] The territory it covered is today divided into the regional county municipalities of Le Granit in the administrative regions of the Estrie and Beauce-Sartigan in Chaudière-Appalaches.
Its capital was the municipality of Lac-Mégantic.
[2][3] The county name comes from that of the governor of New France, Louis de Buade de Frontenac.
The townships in Compton County were Winslow, Whitton, Marston, Chesham and Clinton.
The townships from Beauce County were Price, Lambton, Adstock, Aylmer, Forsyth, Woburn, Dorset, Gayhurst, Spalding, Ditchfield, Louise and Risborough as well as parts of Shenley and Marlow.