You may be interested to see this letter from Arch Gerlach, the Acting Chief at the State Department Division of Map Intelligence and Cartography, to J.K. Wright, the Director of the American Geographical Society, in 1946.
The letter mentions that the OSS Map Division and the Cartographic Branch at the Department of State have been merged, to form the Division of Map Intelligence and Cartography. This was already known [maps], but it’s nice to find a contemporary document.
Source: the original is held in the AGS Archives, Milwaukee, WI, under Wright/Dept. of State.