Historically and geographically, the region known as Bosnia (natively Bosna; Cyrillic: Босна) comprises the northern part of the present-day country of Bosnia and Herzegovina. It lies mainly in the Dinaric Alps, ranging to the southern borders of the Pannonian plain, with the rivers Sava and Drina marking its northern and eastern borders. The southern, Mediterranean, region of the country is Herzegovina.
The area of Bosnia comprises approximately 41,000 km², and makes up about 80% of the territory of the present-day state of Bosnia and Herzegovina. There are no true borders between the regions in Bosnia and Herzegovina, and, unofficially, Herzegovina is south of Ivan-planina.
The two regions have formed a geopolitical entity since medieval times, and the name "Bosnia" commonly occurs in historical and geopolitical senses as generally referring to both regions (Bosnia and Herzegovina). The official use of the name including both regions started only in the late period of Ottoman-rule.
