Beautiful! Is this Italy or Switzerland, Massimo?
It is Italy, but it's on the Danube basin (border with Switzerland).
The border has some quirks, and does not follow exactly the Continental Divide, one big quirk is the entire Canton Ticino, which is on the S side of the Alps and of course is Switzerland, then you'll have the S side of Bernina Pass (Poschiavo, again Switzerland: spectacular Bernina Train from St.Moritz to Tirano), and then the Livigno valleys (Italy).
Livigno is a duty-free area for historical reasons, because in the past it was isolated for 6 months in winter from "civilization", nowadays on account of the duty free area its roads are the first ones to be plowed and cleaned.
Ciao from Massimo