The Stryama is a river in southern Bulgaria, an important left tributary of the Maritsa. It originates in the Balkan Mountains. The river is 110 kilometres in length and is the sixth longest in the Maritsa drainage, following the Tundzha (390 km), the Arda (290 km), the Ergene (281 km), the Topolnitsa (155 km) and the Sazliyka (145 km).

Maritsa or Maritza, also known as Meriç and Evros, is a river that runs through the Balkans in Southeast Europe. With a length of 480 km (300 mi), it is the longest river that runs solely in the interior of the Balkan peninsula, and one of the largest in Europe by discharge. It flows through Bulgaria in its upper and middle reaches, while its lower course forms much of the border between Greece and Turkey. Its drainage area is about 53,000 km2 (20,000 sq mi), of which 66.2% is in Bulgaria, 27.5% in Turkey and 6.3% in Greece. It is the main river of the historical region of Thrace, most of which lies in its drainage basin.