Dumenza is a comune (municipality) in the Province of Varese in the Italian region of Lombardy, located about 70 kilometers (43 mi) northwest of Milan and about 25 kilometers (16 mi) north of Varese, on the border with Switzerland.The municipality of Dumenza contains the frazioni (subdivisions, mainly villages and hamlets) Runo (birthplace of painter Bernardino Luini), Due Cossani, Stivigliano, and Trezzino.Dumenza borders the following municipalities: Agra, Astano (Switzerland), Curiglia con Monteviasco, Luino, Maccagno, Miglieglia (Switzerland), Monteggio (Switzerland), Novaggio (Switzerland), Sessa (Switzerland), Veddasca.