Moggio Udinese borders the following municipalities: Amaro, Arta Terme, Chiusaforte, Dogna, Hermagor-Pressegger See (Austria), Paularo, Pontebba, Resiutta, Tolmezzo, Venzone.

The area had already been settled in Roman times, when a castrum or at least a watchtower was erected to control the traffic on the road from Italy to the province of Noricum in the north.

According to legend, one Carinthian noble Cacellino (Kazelin), a member of the Aribonids dynasty, about 1084/85 ceded his Friulian estates around Moggio to his brother-in-law Patriarch Frederick of Aquileia.

Though the deed of donation has been identified as a fake, it is documented that in 1119 Frederick's successor Ulrich of Eppenstein established a Benedictine monastery at the site, dedicated to Saint Gall.

The monastery was finally dissolved in 1773, a few years later the Moggio area fell to the Habsburg monarchy according to the 1797 Treaty of Campo Formio and became part of the Austrian Kingdom of Lombardy–Venetia by resolution of the Congress of Vienna in 1815.