The Mahananda River (Pron:/ˌməhɑːˈnʌndə or ˌmɑːhəˈnʌndə/) (Nepali: महानदी, Hindi: महानन्दा नदी, Bengali: মহানন্দা নদী) 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.