The Matsesta (Russian: Мацеста, Adyghe: Мэсты Псы,МэшIост) is a river that flows into the Black Sea. The river starts in the southern ranges of the Alek mountains at a height of 900 meters above sea level and flows through the Khostinsky region of Sochi and into the Black Sea. The river is 17 kilometers in length, and the highest point in the river's basin is 1003 meters above sea level. The river has numerous tributaries, the largest of which are the Tsanyk and Zmeyka.

The Matsesta is most famous for its sources of mineral water. The name of the river translates in the Ubykh language and the Circassian(Adyghe) as "fiery water", from the words mašč'o (fire) and psy (water). This was because people that immersed themselves in the water of the Matsesta found that their skin became red. There also exists a legend about a girl named Matsesta who invaded an underground kingdom in order to find the spirit of the mineral resources. She killed the spirit at the price of her own life and then brought the healing sources of the river to its surface.