The Nabaganga (Bengali: নবগঙ্গা নদী, romanized: Nabagaṅgā Nadī) is the fourth-biggest river in Bangladesh and a tributary of the Mathabhanga.

It flows east, where the Kumar and the Chitra rivers join it at Magura and Narail, respectively.

Efforts to steer the river back to its original course proved futile when dredging in the 1930, at Gaznavi Ghat, failed to produce the desired results.

Today, the Nabaganga merges into the Kumar River after flowing through Chuadanga and Jhenaidah Districts.

Most of the water in the Nabaganga River from this point on comes from the Kumar.