Geographically, Bengal Delta region is a distinguished part in South Asia. The word ‘Bangalah' used since 1352 AD. The bengal Sultanate comprises modern day Bangladesh and part of west bengal, india. Historically, both Bengal Sultanate and Sonargaon should be under Bangladesh. In Bengali language 'Desh' means country or state.
During Bengal Sultanate period, except the Capital, most of the important cities are situated in Bangladesh now.