The authors agree that this is a surname proper to the north of the region of Lombardy. E. Rossoni places it specifically in the north of the province of Milan and notes that it could derive from Mount Meregallo, located in the Como area.

Surnames in Italy links it more precisely to the Brianza and documents its initial use as a baptismal name. The earliest attestations correspond to 1155, with Maragallia de Alliate, and to 1171, when a certain Malagallia de Alliate appears among the consuls in the inscription commemorating the rebuilding of the walls of Milan. As a surname, it is recorded from 1201 with Ambrosius Maragallia d'Arosio. In Milan the variant Meregallia also circulated. From the semantic point of view, the surname is held to have designated, in origin, one who raises or consumes cockerels, an interpretation shared with other surnames of the same lexical family.