The town is situated 113 m. above sea level at the foot of a hill dominated by the castle, on the wide alluvial plain of the Tagliamento river.

Despite its probable Roman origin, it is thought to be founded in 983 (document of Emperor Otto). The Patriarchs of Aquileia had their seat here after 1238 on. Often at war with Cividale and Venice, it was conquered by the latter in 1420 and shared its fortunes till the Napoleonic era (1797). After the Congress of Vienna it became a Hapsburg dominion until 1866 when, following the 3rd War of Independence, it was united with Italy.

Monuments: in the 16th-century Piazza della Libertà, at the foot of the castle, is Palazzo del Comune (15th century GothicVenetian style), Porticato di S. Giovanni, an elegant Renaissance loggia (16th century), Torre dell'Orologio (16th century clock tower); not far away stands the Duomo (14th century, restructured in the 18th century, with a rich interior), with the adjacent Oratorio della Purita (18th century, paintings by Tiepolo), church of S. Maria del Castello (12th-13th century with 13th century frescoes), Palazzo Arcivescovile (16th-18th century).

An important junction for both road and rail communications (with links to Croatia and Austria), Udine is a busy centre for commercial activities and freight distribution. The still expanding industrial sector, includes the steel industry, engineering, textiles, paper, food (breweries) and furniture.