Fortanga (Ingush: Форта/Фарта, romanized: Forta/Farta; Chechen: Марта, romanized: 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.

[1] The river originates near the border of Chechnya and Ingushetia on the northern slope of the Tsoreylam (Khaylam) ridge.

The mouth of the river is located near the village of Shaami-Yurt, 7.5 km along the right bank of the Assa River.

[1] 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.