[2] It takes its source from the Vitosha Mountain in Bulgaria, runs first westward, then southward, forming a number of gorges, enters Greece near the village of Promachonas in eastern Macedonia.

Also in Greece, the river entirely flows in the Serres regional unit into the Strymonian Gulf in Aegean Sea, near Amphipolis.

The name Strymón was a hydronym in ancient Greek mythology, referring to a mythical Thracian king that was drowned in the river.

In 437 BC, the ancient Greek city of Amphipolis was founded near the river's entrance to the Aegean, at the site previously known as Ennea Hodoi ('Nine roads').

The ship Struma, which took Jewish refugees out of Romania in World War II and was torpedoed and sunk in the Black Sea, causing nearly 800 deaths, was named after the river.