Calvörde formed a key strongpoint in this regard because it lay at the southern end of the formerly impassable marshy forests of the Drömling at a point that used to be the key crossing of the Ohre river that on the road from Brunswick to the southern Altmark.
Excluded were the eastern areas belonging to Brunswick including the district of Blankenburg and the exclave of Calvörde (part of the district of Helmstedt), which fell within the Soviet Zone and was integrated into the state of Saxony-Anhalt, and the Hanoverian Amt of Neuhaus, which also lay on Soviet-occupied territory and was not united with Lower Saxony until 1993.