On 14 April 2016, to promote a reform on the municipal administrative decentralization, the City Council of Milan established the new Municipality 1, a new administrative body responsible for running most local services, such as schools, social services, waste collection, roads, parks, libraries and local commerce.

It is the least populated of the city's zones and one of the smallest by area, a significant part of which is occupied by Piazza del Duomo, Sforza Castle and Sempione Park.

Rosa  • Cordusio  • Bossi Contrada capitana: Aquila (seat of Palazzo della Ragione, Milan's medieval town hall) Quadrilatero della moda (Italian pronunciation: [kwadriˈlaːtero della ˈmɔːda]; literally "fashion square"), or Via Montenapoleone fashion district, is the high-class shopping district in the centre of the zone, characterized by the presence of numerous boutiques and related retail outlets which represent most of the world's major fashion houses.

The sides of the square, located to the south of the arches of Porta Nuova, are formed by Via Montenapoleone, Via Manzoni, Via della Spiga and Corso Venezia.

The area has its own local authority called Consiglio di Municipio (Municipal Council), composed by a president and 30 members directly elected by citizens every five years.

In this area are located the main buildings of many higher education institutions: The zone houses all the most important museums of the city.