Bulgaria is a country in the Balkans in south-eastern Europe.  Bulgaria borders five other countries: Romania to the north (mostly along the River Danube), Serbia and the Republic of Macedonia to the west, and Greece and Turkey to the south. The Black Sea defines the extent of the country to the east.

With a territory of 110,994 square kilometers, Bulgaria ranks as the 16th-largest country in Europe. Several mountainous areas define the landscape, most notably the Stara Planina (Balkan) and Rodopi mountain ranges, as well as the Rila range, which includes the highest peak in the Balkan region, Musala.  In contrast, the Danubian plain in the north and the Upper Thracian Plain in the south represent Bulgaria's lowest and most fertile regions. The 378-kilometer Black Sea coastline covers the entire eastern bound of the country.  Bulgaria's capital city and largest settlement is Sofia, with a permanent population of 1,405,000 people.