Leoben , city (1991 pop. 28,897), Styria prov., S central Austria, on the Mur River. An industrial center in a former mining region, it has large ironworks, lumber mills, a mining school, and breweries. An armistice between France and Austria, preliminary to the Treaty of Campo Formio , was signed (1797) at Leoben, concluding Napoleon I 's victorious Italian campaign.