It forms the connecting-link between the plateaus of Haute Marne and the Ardennes, and is bounded E.
By that of Marne, S.
By that of Seine-et-Marne, and W.
In the north of the department; the Oise, traversing the northwest, with its tributaries the Serre and the Aisne, the latter of which joins it beyond the limits of the department; and the Marne and the Ourcq in the south.
Wine of medium quality is grown on the banks of the Marne and the Aisne.