The Mahananda River (Pron:/ˌməhɑːˈnʌndə or ˌmɑːhəˈnʌndə/) (, , ) is a trans-boundary river that flows through the Indian states of  West Bengal, Bihar, and Bangladesh. Its right bank tributary, the Mechi River forms part of Nepal's eastern boundary with West Bengal while the Kankai flows out of Nepal.