While this was part of the Illinois Country claimed by French explorers, this area was barely settled by their colonists. Most French colonial villages, such as Prairie du Rocher, were close to the Mississippi River. During the French and Indian War against the British, the French built a fort here in 1757. It was named Fort Massac after Claude Louis d'Espinchal, Marquis de Massiac, the French Naval Minister. Massiac is a commune in Cantal, France. The county was later named after Massac.