Aisae, a department in the north of France which takes its name from the river Aisne, an affluent of the Oise. It consists of portions of He de France, Brie, and Picardy, and is bounded by the departments of Le Nord, Ardennes, Marne, Seine-et-Marne, Oise, and Somme, and Belgium. Area, 2,838 sq. m.; pop. in 1872, 552.439. It is traversed by the Oise, Aisne, Ourcq, and Marne. The surface is mostly flat, and the soil fertile. It is divided into the ar-rondissements of St. Quentin, Laon, Chateau-Thierry, Soissons, and Vervins. Capital, Laon. The quantity of farm produce and live stock exceeds that of most parts of France. A profitable trade is carried on in pressing oil from the beech mast of the extensive forests. Several of the towns are noted for their manufactures. The mirrors of St. Gobain are known throughout France.