Eastern Indo-Aryan languages

The Eastern Indo-Aryan languages, also known as Māgadhan languages, are spoken throughout the eastern region of the Indian subcontinent, which includes Bihar, Uttar Pradesh, Jharkhand, Bengal region, Tripura, Assam, and Odisha; alongside other regions surrounding the northeastern Himalayan corridor. Bengali is official language of Bangladesh and the state of West Bengal, Tripura and the Barak Valley of Assam while Assamese and Odia are the official languages of Assam and Odisha, respectively.

Source: Wikipedia — Eastern Indo-Aryan languages (CC BY-SA 4.0)