Ergene is a major left tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of the Maritsa

Maritsa

The Maritsa or Evros , ) is, with a length of 480 km, the longest river that runs solely in the interior of the Balkans. It has its origin in the Rila Mountains in Western Bulgaria, flowing southeast between the Balkan and Rhodope Mountains, past Plovdiv and Parvomay to Edirne, Turkey...

 (Meriç) river, flowing entirely in the East Thrace

East Thrace

East Thrace or Eastern Thrace , also known as Turkish Thrace, is the part of the modern republic of Turkey that is geographically part of Europe, all in the eastern part of the historical region of Thrace; most of Turkey is in Anatolia, also known as Asia Minor. Turkish Thrace is also called...

 region of Turkey

Turkey

Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...

.

The river rises from the southern part of Strandzha

Strandzha

Strandzha is a mountain massif in southeastern Bulgaria and the European part of Turkey, in the southeastern part of the Balkans between the plains of Thrace to the west, the lowlands near Burgas to the north and the Black Sea to the east. Its highest peak is Mahya Dağı in Turkey, while the...

 mountain, not far from the Black Sea

Black Sea

The Black Sea is bounded by Europe, Anatolia and the Caucasus and is ultimately connected to the Atlantic Ocean via the Mediterranean and the Aegean seas and various straits. The Bosphorus strait connects it to the Sea of Marmara, and the strait of the Dardanelles connects that sea to the Aegean...

 and flows for 281 km before entering the Maritsa near the Turkish city of İpsala

Ipsala

İpsala is a town and district of Edirne Province in northwestern Turkey. It is the location of one of the main border checkpoints between Greece and Turkey. The Greek town opposite İpsala is Kipoi. The population is 8,332 and 30,112 ....

, with part of its lower course canalized. Its drainage basin has an area of 17,323 km².

Major settlements along the river include Uzunköprü

Uzunköprü

Uzunköprü is a small town and a district of Edirne Province in northwestern Turkey.It is on the railway line from Istanbul towards Sofia, Belgrade and western Europe, and a frontier post on the Greek border.- Long Bridge :...

, Pehlivanköy

Pehlivanköy

Pehlivanköy is a town and district of Kırklareli Province in the Marmara region of Turkey. The mayor is Hüseyin Açıkel . The population is 2,007 as of 2010.-External links:* *...

, Çerkezköy

Çerkezköy

Çerkezköy is a town and district of Tekirdağ Province in the Marmara Region of Turkey.-Facts:The district is located in inland Thrace just to the west of the outlying Istanbul districts of Çatalca and Silivri. Çerkezköy is an industrial area. It is from Tekirdağ and from Istanbul but in many ways...

 and Muratlı

Muratli

Muratlı is a town and a district of Tekirdağ Province in the Marmara region of Turkey. It is located at 24 km north of the town of Tekirdağ and on the railway line from Istanbul to the Bulgarian border. It covers an area of 427 km², and the population is about 20,000. The district has hot...

.