This article is about the region in Republika Srpska, Bosnia and Herzegovina. For the region in Montenegro, see Old Herzegovina
East Herzegovina (Serbo-Croatian: Istočna Hercegovina; Serbian Cyrillic: Источна Херцеговина) is the east part of the historical Herzegovina region (i.e. of Duchy of Saint Sava and Sanjak of Herzegovina), located in Bosnia and Herzegovina, east of the Neretva river, Major towns are Trebinje, Nevesinje, Foča and Bileća, located in Republika Srpska, predominantly inhabited by ethnic Serbs (see Serbs of Bosnia and Herzegovina). West Herzegovina is west of the Neretva river, and is today administratively part of the Herzegovina-Neretva Canton and West Herzegovina Canton, predominantly inhabited by ethnic Croats. The eastern parts of historical Herzegovina lie in Montenegro, in so-called "Old Herzegovina", which became part of the Principality of Montenegro in 1878. In 1991, local ethnic Serbs of the region declared the territory of SAO East Herzegovina independent and joined other Serb territories into Republika Srpska by 1992. The meso-region has since been named Trebinje Region (Regija Trebinje/Регија Требиње).
The "Association of Municipalities of Herzegovina"