The Hindi belt is a common reference to the North Indian region were Hindi is spoken, i.e. the states of Bihar, Uttar Pradesh, Madhya Pradesh, Haryana, Rajasthan, Himachal Pradesh, Uttaranchal, Chhattisgarh, and Jharkhand, as well as the National capital territory of Delhi.
Although Hindi is also the principal language spoken in Mumbai (formerly Bombay), this is a linguistic island lying outside the Hindi belt.