Unter-Počernitz is a place, that before the Treaty of Saint-Germain belonged to Austro-Hungary and was situated in the administrative region Karolinenthal.
Unter-Počernitz was formerly part of the German Empire. In the German Empire, the place was called Dolní Počernice. The place is now called Dolní Počernice (Praha-Dol. Počernice) and belongs to Czech Republic.