The Osam is a river in northern Bulgaria

Bulgaria

Bulgaria , officially the Republic of Bulgaria , is a parliamentary democracy within a unitary constitutional republic in Southeast Europe. The country borders Romania to the north, Serbia and Macedonia to the west, Greece and Turkey to the south, as well as the Black Sea to the east...

. Its drainage basin

Drainage basin

A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

 is in between that of the river Vit

Vit

The Vit also Vid is a river in central northern Bulgaria with a length of 18 km. It is a tributary of Danube. The source of the Vit is in Stara Planina, below Vezhen Peak at an altitude of 2,030 m, and it empties into the Danube close to Somovit...

 to the west and the Yantra

Yantra

Yantra is the Sanskrit word for "instrument" or "machine". Much like the word "instrument" itself, it can stand for symbols, processes, automata, machinery or anything that has structure and organization, depending on context....

 system to the east. The river has two main tributaries in its upper course: the Black Osam takes its source from the foot of Levski Peak

Levski Peak (Bulgaria)

Levski Peak is a peak in the central Balkan Mountains, in Lovech Province, Bulgaria. It is named after the famous Bulgarian revolutionary Vasil Levski. The peak is high and is situated on the main ridge of the mountain range to the west of Golyam Kupen Peak....

 in the Balkan Mountains

Balkan Mountains

The Balkan mountain range is a mountain range in the eastern part of the Balkan Peninsula. The Balkan range runs 560 km from the Vrashka Chuka Peak on the border between Bulgaria and eastern Serbia eastward through central Bulgaria to Cape Emine on the Black Sea...

, at an altitude of 1821 m (5,974 ft), while the White Osam has its source on the northern slopes of the Kozya Stena peak. In Troyan

Troyan

Troyan is a town in Lovech Province in central Bulgaria with population of 21,997 inhabitants, as of December 2009,. It is the administrative centre of the homonymous Troyan Municipality. The town is about 160 km away from the country capital Sofia. The nearest civilian airport is Gorna...

, the black and white Osam join. It runs north towards Lovech

Lovech

Lovech is a town in north-central Bulgaria with a population of 36,296 as of February 2011. It is the administrative centre of the Lovech Province and of the subordinate Lovech Municipality. The town is located about 150 km northeast from the capital city of Sofia...

, then north-east until Letnitsa

Letnitsa

Letnitsa is a town in central northern Bulgaria, part of Lovech Province. It is the administrative centre of the homonymous Letnitsa Municipality and lies in the northeastern part of the province, close to the town of Levski...

 and Levski

Levski (town)

Levski is a town in central northern Bulgaria, an administrative center of the homonymous Levski Municipality in the very southeast of Pleven Province. It is located in the valley of the Osam River and was called Karağaç during the Ottoman rule of Bulgaria and until 1897, when it was renamed...

, where it turns north-west until it flows into the river Danube

Danube

The Danube is a river in the Central Europe and the Europe's second longest river after the Volga. It is classified as an international waterway....

 5 km west of the town of Nikopol

Nikopol, Bulgaria

Nikopol is a town in northern Bulgaria, the administrative center of Nikopol municipality, part of Pleven Province, on the right bank of the Danube river, 4 km downstream from the mouth of the Osam river. It spreads at the foot of steep chalk cliffs along the Danube and up a narrow valley...

. The ancient name of the river was Assamus.