In the context of India Post tracking, BO stands for Branch Office. When a package is dispatched to BO, it means that the shipment has been dispatched to the Branch Office closest to the recipients address. The Branch Office is responsible for delivering the package to the addressee. BOs work under Sub Offices (SOs), which in turn are controlled by Head Offices (HOs) . All BOs come under an SO, and each Post Master of an SO is controlled and answerable to the HO Post Master or Director.