Casorate Sempione is a comune (municipality) in the Province of Varese in the Italian region Lombardy, located 40 kilometres (25 mi) northwest of Milan and about 20 kilometres (12 mi) southwest of Varese. As of 31 December 2004, it had a population of 5,334 and an area of 6.9 square kilometres (2.7 sq mi).[3]