Breg is not only a common toponym in Slovenia, but also has equivalents in other Slavic languages (e.g., Brijeg in Bosnia and Herzegovina, Břehy in the Czech Republic, Brehy in Slovakia, and Brzeg in Poland), all derived from the Slavic common noun *bergъ 'slope, bank'.
Břehy is the name of several places in the Czech Republic and Slovakia.
Brehy, Žarnovica District | Břehy (Pardubice District) | Břehy | Brehy |