The 386,000 m2 Sempione Park, or Parco Sempione in Italian, is a city park near to the Sforzesco Castle in the old town of the Lombard capital.

The park was erected in 1890 on what had previously been a piazza d'armi (military formation) plaza. When the Sempione Tunnel opened in 1906, the garden was given that name. Starting from the park, a route leads to Switzerland and the tunnel connecting Piedmont and Canton Valais.

Emilio Alemagna, an Italian architect, created the park.

The park is home to a variety of international tree species, including holly (Ilex aquifolium), catalpa (Catalpa bignonioides), cedars (Cedrus atlantica, Cedrus deodara, and Calocedrus decurrens), beech (Fagus sylvatica 'Aspelinifolia', 'Pendula', and 'Purpurea (Sophora japonica). Numerous examples of American oak (Quercus rubra), yew (Taxus baccata), lime (Tilia americana and Tilia platyphyllos), marsh cypress (Taxodium distichum), and a few types of maple trees can be found (Acer negundo, Acer campestre, Acer pseudoplatanus, Acer platanoides and Acer saccharinum).

There are a few significant trees, including an elm (Ulmus minor) close to the Napoleon III stadium, a horse chestnut (Aesculus hippocastanum) close to the ponte delle sirenette, and a plane tree (Platanus acerifolia), which is notable for its shape, close to a small lake.

The park is a favorite among Milanese of all ages since it has lawns for lounging and tanning, playgrounds for kids, walkways for everyone, and romantic nooks.

The Triennale Palace, the Arch of Peace, the Milan Arena, the Civic Aquarium, and the Branca Tower are all located in the park.

Additionally, there are six kiosks with bar service, four dog-friendly spaces, and restrooms in the spring and summer.

Thanks to the City of Milan, there is free wireless Internet access available throughout the park. At the relevant locations in the park, a free registration card (scheda di registrazione for internet in Italian) must be picked up. Three hours are on the card.