Nepali with more than 16 million speakers world wide, has more than 3 million speakers in India. Nepali is one of the 22 scheduled languages of india. The speakers of Nepali are distributed across India, even though a more concentration of speakers of Nepali language is in North Eastern India.
From the English Wikipedia article about Nepali language:
In India, there are a large number of Nepali-speaking people. There are an estimated 500,000 Nepali speakers in Sikkim (where Nepali is the official state language.) In Darjeeling and Jalpaiguri districts of West Bengal, there are about 1,400,000 Nepali speakers. In North-East India (states of Assam, Meghalaya, Nagaland, Manipur, Tripura, Mizoram and Arunachal Pradesh), there are several million Nepali speakers. A considerable number of Nepali-speaking people are also present in many Indian cities such as Kolkata, Delhi, Bangalore, Visakhapatnam, Chennai, Mumbai and Hyderabad.