Source: Istat (1994) Resident population of municipalities - Censuses from 1861 to 1991 (Territorial districts as of 20 October 1991).
The increment rate is computed from the compound interest formula, taking as time intervals those between Census dates.
In 1866, following the Third Italian Independence war, the Veneto district (then including the Udine district) and the Mantova district municipalities are annexed to Italy. Census data until 1911 are missing for the municipalities annexed after World War 1 and that formed Venezia Giulia and Venezia Tridentina.
Some municipalities belonging to the Hapsburg Empire between 1871 and 1911 and being part of the territories annexed to Italy after World War 1 have been ascribed to Italy. They are Pontefella and Laglasie San Leopoldo, whose populations have been ascribed to the Udine province. This is an exception to the rule by which the figures of those municipalities which have been annexed after the Reign of Italy establishment should be considered starting from the first census following their annexation. The population registered by the austrian censuses has been ascribed to these municipalities.
The following population amounts have been ascribed to the Udine province for the censuses from 1871 to 1911.
In 1920, following World War 1, the territories forming Venezia Giulia (including the areas of Gorizia and Gradisca, Carinzia and Carniola, Istria and, finally, Zara) are annexed to Italy in fulfilment of the 1920 Rapallo treaty. The municipality of Fiume, which will be annexed in fulfilment of the 1924 Roma treaty, and the area of Venezia Tridentina (then including the province of Trento) are not included in this annexation.
In 1947, following World War 2 some municipalities from the provinces of Goriza and Trieste and the provinces of Fiume, Pola and Zara are transferred to ex-Jugoslavia:
The resident population - 1936 Census - with current borders - of Friuli-Venezia Giulia can be reconstructed in the following way:
* Source: Istat (2001) Unità amministrative - Variazioni territoriali e di nome dal 1861 al 2000 (Popolazione legale per Comune ai censimenti dal 1861 al 1991 ai confini dell'epoca).