The name of this commune at the foot of the Black Mountains comes from "rodoerd" and "kalleg" meaning "ford" and "rocky". The menhir of Guernangoué, dated from the final Neolithic, testifies to the antiquity of the occupation of this land. Like Gourin, a neighboring commune, Roudouallec experienced the phenomenon of the emigration of his population to the United States. An Air France office is established here, at one time! Nicholas the Great, tailor at Roudouallec, was one of the first to dare cross the Atlantic to try his luck. It was in 1881. His prolonged absence suggested that he was devoured by the bears or killed by the Indians. Yet he was seen returning years later, much richer than his departure!