Italian and Italian dialects express indefiniteness in different ways, among which with a null determiner (ZERO) like all other Romance languages, but also with the definite article (ART) unlike what is found in Romance. Italian and some northern Italian dialects also display the so-called “partitive determiner” DI+ART, which is present in French. Few northwestern Italian dialects display (bare) DI, parallel to French. We adopt Cardinaletti and Giusti’s (2015, 2016) unified analysis and build on Cardinaletti and Giusti’s (2018, 2020) hypothesis that the variation and optionality in the distribution of the four determiners in regional Italian mirror their distribution in Italian dialects along two isoglosses: the ART isogloss spreading from the center of Italy towards north-west and south-east; and the DI isogloss spreading from Piedmont eastwards. We conduct a quantitative analysis on the results of a questionnaire in Piacentino and Rodigino. We test the distribution of the four determiners with mass and count nouns in two dimensions: sentence type (positive vs. negative) and predicate type (telic vs. atelic). The results confirm the hypothesis that the complexity of the determiner is related to its distribution highlighting two hierarchies of contexts: NEG < POS and ATEL < TEL. It also confirms that Piacentino, located at the crossroads of the ART and DI isoglosses, has more optionality than Rodigino, located at their borders.