wikipedia defines Bhojpuri as:

Bhojpuri is a regional language spoken in parts of north-central and eastern India. It is spoken in the western part of state of Bihar, the northwestern part of Jharkhand, and the Purvanchal region of Uttar Pradesh, as well as an adjoining area of southern plains of Nepal. Bhojpuri is also spoken in Guyana, Suriname, Fiji, Trinidad and Tobago and Mauritius. The language of the Surinamese Hindus, however, is seldom referred to as Bhojpuri but usually as Sarnami Hindi or just Sarnami.
According to an article published in Times of India, an estimated 70 million people of Uttar Pradesh and a further 80 million people in Bihar speak Bhojpuri as their first or second language. There are 6 million Bhojpuri speaking people are living outside the Bhojpuri heartlands of Bihar and Purvanchal. These areas include Nepal, Mauritius, Fiji, Suriname, Guyana, Uganda, Singapore, Trinidad & Tobago, Great Britain, and United States. This makes the total Bhojpuri speaking population in the world close to 150 million.