The name of the Park derives from an ancient structure used for hunting purposes for bird trapping, an activity practised since the 16th century in upper Lombardy and Veneto, and is now forbidden. The "Roccolo" was therefore a hunting post with a hut or a tower-shaped building, surrounded by greenery, very often hornbeam, created specifically to attract birds.
The Parco del Roccolo plays a very important territorial and environmental role in a highly urbanised area such as the Alto Milanese, representing a fundamental ecological path connecting the Ticino and Olona rivers.
The Park territory is mainly made up of agricultural areas, irrigated by a complex system of irrigation ditches deriving from the Villoresi Canal.
The Villoresi Canal, designed by Engineer Eugenio Villoresi in 1891, draws its water from the Ticino River to irrigate a wide area of the Milanese plain as far as the Adda River, where it ends. Three "secondary" canals start from this area in the Park territory, carrying the water towards the territories further south. The Corbetta secondary canal, branching off from the Villoresi in the "Quattro bocche" locality in Busto Garolfo, is of particular interest.
The Park also contains a number of lakes, resulting from mining activities.