The name of the district comes from the Strada del Portello (Portello road), an ancient rural road that used to connect Milan to Rho, and that was later replaced by the new Strada del Sempione (Simplon Road) leading to the Simplon Pass; the old Portello road is now known as Via Traiano. In turn, the road was named after the Portello city gate, that was part of the city walls and that was located in the surroundings of the modern Cadorna railway station.