E. De Felice locates this surname in southern Sardinia and traces it to a nickname derived from the Campidanese Sardinian word mùrgia, meaning "brine" and, through a crossing with mùrcia, also "dregs, sediment."

E. Rossoni agrees on the derivation from the Sardinian dialect term murgia in the sense of "brine" — that is, very salty water — and further specifies that the word descends from the Latin muria. Rossoni diverges from De Felice on geography, arguing that the surname is not confined to the southern part of the island but is distributed evenly throughout Sardinia. He also provides substantial historical documentation: the surname appears among the signatories of the Peace of Eleonora of 1388, and earlier attestations are found in the Condaghe di San Nicola di Trullas and the Condaghe di Santa Maria di Bonarcado, both sources dating to the eleventh and twelfth centuries.

It is also recorded, more broadly, as deriving from the Sardinian word for "brine" or "pickle."