The Châlons military camp, 16 miles (26 km) north, was founded under Napoleon III in 1856. Occupied by the Germans from 1940 to 1944 in World War II, the town was heavily bombed in April and July of 1944. The 13th-century cathedral of Saint-Étienne suffered some damage then but has been restored. The cathedral has a 17th-century west facade, fine 13th-century stained-glass windows, and a remarkable main altar. The collegiate church of Notre-Dame-en-Vaux (12th century) is a mixture of Gothic and Romanesque styles and has stained-glass windows dating from 1525 and 1526, a Gothic choir, and a carillon of 56 bells. Stained-glass windows are also a feature of the churches of Saint-Alpin and Saint-Jean-Baptiste. Near the town hall is a 13th-century house containing manuscripts from the 12th to the 15th century and incunabula.
Châlons is an important local administrative and commercial centre and has an outpost of the University of Reims. It also has a well-established industrial sector that includes the manufacture of electrical and mechanical machinery, automotive parts, and detergents. Pop. (1999) 47,339; (2014 est.) 45,002.