Busto Arsizio is a comune located in the south-easternmost part of the province of Varese, within the Lombardy region of northern Italy. Situated approximately 35 kilometres (22 mi) north of Milan, it serves as a significant urban center in the area.
The municipality is characterized by its economic activity, which is primarily based on industry and commerce. It holds a prominent demographic position in the region, ranking as the fifth most populous municipality in Lombardy and the largest in the province of Varese.