town, a southern suburb of Paris, Essonne département, Île-de-France région, north-central France, on the Seine River. It is a river port, with diversified manufactures, and has a 12th-century church and a château (now a seminary) with 17th-century gardens designed by André Le Nôtre. Viry-Châtillon Lake offers various facilities for water sports. Pop. (1999) 30,257; (2005 est.) 30,600.