Bhilsa, India.
I live in Bhopal which lies in that province, which is in the Malwa region in the central area of India (an independent kingdom in EU4 start date). I have also lived in Bhilsa itself (province capital in EU4, now renamed back to the ancient name of Vidisha). Historically this area has been the main strategic crossroad between northern and southern India, and the largest Indian battle of the 18th century happened right here.
A land of spread-out fortresses and palaces, farms, hills and ever-content servile cosmopolitan population.
Used to be a rich region until the British plundered it almost completely.