It was annexed by Venice in 1420 and control over Udine was granted to Tristano Savorgnan, the leader of a family in the city.

The province is located in the lowlands of the Po-Venetian Valley, south of the Venetian Prealps and the Alpine foothills of Friuli.

The southwesterly part of the province is flat, low-lying land farmed and irrigated intensively, and the coast has beaches, sand dunes and lagoons.

To the southeast, the land is higher where the limestone Karst Plateau reaches the Adriatic, and there are cliffs on the coast.

The soil is porous and much of the water from the mountains flows underground to resurface as a zone of springs on the plain.