Antonio Sciarretta's Toponymy
Before the Roman conquest, the region was inhabited by many tribes and confederations, namely, Vediantii, Nerusii, Deciates, Oxybii, Comani, Anatilii, Desuviates, Salyes, Albici, Vulgientes, Memini, Cavares, Vocontii, Avantici, Bodiontici, Sogiontii, Caturiges, Ucenni, Allobroges, Segovellauni, and Ceutrones east of the river Rhone, Volcae Arecomici, Ruteni, Volcae Tectosagi, and Sardones west of the Rhone. This page includes the toponyms of the separated Roman provinces of Alpes Cottiae, Alpes Maritimae, and Alpes Graiae.
Common remarks: the place-names have been put in the nominative case, an asterisk * means not attested, reconstructed form. The late place-names of probable Latin origin have not been included. The IE roots are in the form given by Pokorny's Indogermanische Wörterbuch. The links will be active when the single pages will be published, see the main page. For any comment, suggestion, email me.
Other strata are more difficult to identifiy. There is some evidence of a non-negligible A-language stratum in the coastal south of the region. Apart from this vocalism (and the presence of p- which contrast to known Celtic languages), no other particular shifts seemingly characterize this stratum. We might be tempted to attribute these toponyms, often hydronyms, to the Alteuropaeisch ('old European') stratum first proposed by H. Krahe as a substrate to historically known Celtic, Germanic, etc. languages.
Given the territorial continuity to Liguria in Italy, where two distinct non-Gaulish strata were identified - a possibly Celtic but pre-Gaulish one and a Liguro-Sicanian one - some of the A-language toponyms could actually belong to one of these two strata, particularly the Liguro-Sicanian one that was surely an A-language.
Finally, near the borders of Spain, there is at least one clear example of a name explained by Basque language, which points at an Vasco-Iberian superstratum that partially displaced a previously A-language or Celtic domain.
Greek names are of course rather popular in the coastal areas colonized by Greeks in the 1st millennium BC.