From Wikipedia:
Podolski (Polish feminine: Podolska, plural: Podolscy), (Ukrainian: Подольский) is a Slavic surname found mostly in Poland and Ukraine. It refers to the historical region of Podolia, located in present-day Ukraine.
https://en.wikipedia.org/wiki/Podolski_(surname)
Here is another article which has information about Podolia and its location. It includes a map.