Aisne borders the Ardennes Forest and Belgium to the northeast, in the region of Picardy. The Aisne River crosses the area from east to west, where it joins the Oise River. The landscape is dominated by masses of rock which often have steep flanks. These rocks appear all over the region, but the most impressive examples are at Laon and the Chemin des Dames ridge.

The principal cities in Aisne are : Laon, pop. 26,000 (capital), Saint-Quentin, pop. 60,000, Soissons, pop. 30,000, Château-Thierry, pop. 15,000, Tergnier, pop. 15,000

Aisne is surrounded by the region of champagne-ardenne with the departments of Ardennes and Marne, by the region of Ile de France by the deparment of Seine et Marne.

Most of the old growth forests in the area were destroyed during battles in World War I. The French offensive against the Chemin des Dames in spring 1917 is sometimes referred to as the Second Battle of the Aisne.

Aine griculture dominates the economy, especially cereal crops. Beet sugar is one of the most important industrial crops of the area. Silk, cotton, and wool weaving flourish in Saint-Quentin and other towns. Saint-Gobain is known for its production of mirrors, which started in the 17th century. Guise is the agricultural centre of the northern area of Aisne.

It is thought that the Aisne River was the birthplace of the Trench Warfare seen throughout the First World War, as the BEF had initial early successes which drove the Germans back to the Aisne River. The German Troops dug in and managed to hold out against both British and French attacks. With this German success it was to mold the entire face of World War I as both sides began digging in and fortified their positions, thus beginning the Stalemate that was to become the significant feature of the First World War.

There is an average of 500 to 750 mm precipitation annually.