(ancient Lucio), a town of France in the department of Vendée, situate on the edge of a marshy plain, at the extremity of a canal of the same name, 10 miles in length, which traverses the marshes of Fraissay and St Michel-en-l'Herm, and joins the sea at the little Bay of Aiguillon. It is large, with dirty tortuous streets, and very unhealthy. It has a good trade in grain and cattle. The only building worthy of note is its cathedral, of Gothic architecture. It possesses a communal college, and is the seat of a bishop. It was to this see the celebrated Cardinal Richelieu was elevated at the age of twenty-two. The Republicans sustained a defeat under the walls of Lucon in 1793; and the insurgent Vendean besieged the place some months afterwards, but without success.