USID

United States Identification Number. A 9-digit number used to identify Corps/Region, Province, District, Village, and Hamlet in the Republic of Vietnam.

The USID format seems to be as follows:

CPPDDVVHH

Where the digits identify:

• C: Military Region. Vietnam was divided into four military corps (=MRs), values 1, 2, 3 and 4.
• PP: Province
• DD: District
• VV: Village
• HH: Hamlet

The Hamlet Evaluation System (HES) Gazetteer provides a mapping from USID to more meaningfull information (to Universal Transverse Mercator coordinate system (UTM) coordinates).