Herzegovina (Bosnian/Croatian: Hercegovina, Serbian: Херцеговина) is in Bosnia and Herzegovina.
Herzegovina is one of the two traditional regions making up the country of Bosnia and Herzegovina (the other being, perhaps non-surprisingly, Bosnia), and forms the southern quarter of the country. It borders Croatia to west, Montenegro to southeast, and has a tiny coastline on the Adriatic at Neum, the sole window of the country to the sea.
Although mass displacements and ethnic cleansings of the locals took place during the Yugoslav Wars of 1992–1995, the region still has a multi-ethnic community (though not to the extend that it was before the war) and is roughly divided in half between the two political entities of the country: Bosniak/Croat-majority Federation occupies the western half, while Serb-majority Republic of Srpska occupies the eastern half.
The most visited places in Herzegovina are Međugorje and Mostar, in that order. Široki Brijeg, Grude, Ljubuški and Posušje make up Western Herzegovina, the region of ardent Croat nationalism, enormous Catholic churches, wedding halls, countless bars/clubs blaring kitschy pop-folk music and gastarbeiters who return from Germany with Mercedes-Benz cars and build lavish houses. Along the Neretva river you will find Čapljina and the beautiful medieval fortress of Počitelj. Radimlja, near Stolac, has an impressive stećak necropolis with intricately adorned medieval tombs. Eastern Herzegovina, the Serb-inhabited region, is rarely visited by tourists, even though it is home to Trebinje, a pleasant town full of Ottoman architecture and only 30 km from Dubrovnik.
Although slightly inland as it is separated from the coastline by a portion of Croatia, southern parts of Herzegovina enjoy a mild Mediterranean climate while northern parts are under influence of continental climate with cold winters.
All three major languages of the country (Bosnian, Croatian, Serbian) are spoken natively in the region. As these three languages are mutually intelligible, travellers speaking any of them will have no problems in communicating with locals throughout the region. However, as local Serbs prefer the Cyrillic alphabet over Latin, you may need to get acquainted with Cyrillic for a smooth experience in the eastern parts of Herzegovina.