The Alfa Romeo Arese Plant was a plant area where Alfa Romeo had its head office for more than two decades prior to 1986 was known to be. After Fiat Group purchased Alfa Romeo in 1986, Arese became one of the assembly plants of Fiat Group. The factory is in the Province of Milan in the Italian region Lombardy, located about 12 kilometres (7.5 mi) northwest of Milan. The Arese plant replaced the old Alfa Romeo Portello factory and its construction was started in 1960 and took three years and until the end of the 1990s it was the biggest plant of Alfa Romeo covering a very wide area, partly in the territories of Lainate and Garbagnate Milanese. The factory became known as the Arese plant only because the main entrance is in the municipality of Arese.