Santa Maria la Longa is a comune located in the Italian region of Friuli-Venezia Giulia. It is situated within the regional decentralization entity of Udine, positioned in a central location in the plain of Friuli.
The municipality is located approximately 15 kilometres southeast of Udine and about 50 kilometres northwest of Trieste. The area consists of the chief town of Santa Maria la Longa along with the hamlets of Tissano, Mereto di Capitolo, Santo Stefano Udinese, and Ronchiettis.