ALLIER (anc. Elaver), river of central France flowing into the Loire. Rising in the department of Lozere, its upper course is mostly through deep gorges following structural lines of weak ness between the mountains of the Margeride and those of the Velay. It then traverses the basins of Langeac and Brioude, re ceives torrents from the mountains of Dore and Dome, and flows through a wide but shallow channel in the fertile wheat-growing plains north of Clermont Ferrand, being joined by the Sioule above Moulins, the chief town on its banks. It reaches the Loire, 4m. W. of Nevers, after a course of 269m. (154 navigable). Its basin has an area of 6,755 square miles.