Allier is a department in south-central France. Look up allier in Wiktionary, the free dictionary. Allier may also refer to: Allier (river), in France Allier, Hautes-Pyrénées, a commune of the Hautes-Pyrénées department, in southwestern France Carolina Allier, Mexican badminton player Thomas Allier (born 1975), French BMX rider This disambiguation page lists articles associated with the title Allier.If an internal link led you here, you may wish to change the link to point directly to the intended article.