| Fortanga | |
| Subdivision Type1: | Country |
| Source1 Coordinates: | 42.8639°N 45.0247°W |
| Mouth Location: | 7,5 km along the right bank of the Assa river |
| Mouth Coordinates: | 43.2433°N 45.3919°W |
| Basin Size: | 526km2 |
| Pushpin Map: | Caucasus mountains#Russia Ingushetia#Russia Chechnya# |
Fortanga (Ingush: Форта/Фарта|Forta{{noitalic|/; Chechen: Марта|Marta) historically sometimes referred as Balsu, is a river in North Caucasus that flows in Ingushetia and Chechnya. The length of the river is 69 km, the basin area is 526 km2.
The river originates near the border of Chechnya and Ingushetia on the northern slope of the Tsoreylam (Khaylam) ridge.[1] In the upper course it is called Martanka.[2] Flows to the northeast. The mouth of the river is located near the village of Shaami-Yurt, 7.5 km along the right bank of the Assa River. The length of the river is 69 km.
Settlements standing in the Fortanga river basin: Khay, Khayara, Tsechakhki, Singalhi, Gand-Alie, Phumatiye, Katargashtiye, Mulkaniye, Muzhak, Mashtie, Mazanty, Dekashari, Gozuni, Meredzhi, Dakih, Khaykhara, Gerety, Dalg-Bukh, Dak-Bukh, Egichozh, Egiboss, Dattykh, Belkhara, Gandalbos, Arshty, Izdig, Futtunchie, Akati, Bereshki, Samiogochie, Mergyiste, Bamut, Achkhoy-Martan, Shaami-Yurt.