The provincial archives in Venezia (Venice) has begun digitization of the military conscription records of this province. The military conscription project is several years underway but is not yet complete. However, they have made a good start.
These records can be used to find the town of origin of your immigrating ancestor when all you know is the province they came from. The high increase in requests for these records for dual citizenship purposes is indicated as the main precipitating factor in this digitization project.
Military Conscription Records
There are also some great, very old maps of this area of Italy available in .pdf form.
List of Available Maps
For those of you who may be engaged in deep scholarly study of this region's history there are a few other online resources available for you on their website.
Other Research Resources
Have fun! Let me know if this information helps you in your research!