The name has nothing to do with Poland Полска (Polska) in Bulgarian is field related (Поле - field) but why they called like this being in mountain pass (very low mountain but never the less) if you are interested here is a wiki page but You need to use google translate Полска Скакавица – Уикипедия no etymology of the name thouBeautiful place, I envy you for being there. I'm from Poland and I had to check where it is.
Do you know why does it have this name ?