The Département de l’Allier (03) is in central France. It is drained by the Cher (in the far west, around Montluçon), the Loire (which forms much of the eastern border) and the Allier itself (somewhat east of centre) as each of these rivers flows generally northwards out of the Massif Central.
The greater part of the department had formed the greater part of Bourbonnais before 1790, the rest coming from Auvergne. Its territory had been the core of the straggling généralité of Moulins.
In 1960 the department became part of the region of Auvergne.
The capital is Moulins, once the capital of Bourbonnais and residence of an intendant. The subprefectures for the other arrondissements are Montluçon (in the west) and Vichy (in the south). Vichy, then the centre of administration for France with Paris occupied by the Germans, replaced La Palisse (in the southeast). Until 1926 there was a fourth arrondissement with Gannat, near Vichy, as sub-prefecture.