The purpose of the 2020 Census Federally Affiliated Count Overseas (FACO) operation was to obtain counts, by home state, of U.S. military and federal civilian employees stationed or assigned overseas and their dependents living with them at the overseas post/duty station as of April 1, 2020. Home state is a person’s state of residence in the United States, while they are stationed or assigned overseas, based on the employer’s administrative records. Overseas was defined as anywhere outside of the 50 states and the District of Columbia. Counts were obtained from administrative records and were used to allocate the federally affiliated population living overseas to their home state for the sole purpose of using these counts when apportioning seats in the U.S. House of Representatives. Forty U.S. federal departments/agencies provided certified counts, by home state, for their federally affiliated employees and their dependents living with them overseas.

During the 2010 Census, military and civilian employees of the U.S. government who were deployed, stationed, or assigned outside the United States, and their dependents living with them outside the United States, were counted, using administrative data, in their home state for apportionment purposes only. They were not included in the resident population for redistricting.

The 2020 FACO operation was impacted by a change in the 2020 Census Residence Criteria and Residence Situations, defining where people are counted during the 2020 Census. The 2020 Census Residence Criteria defined that military and civilian employees of the U.S. government who were deployed outside the United States, while stationed or assigned in the United States, should be counted at their usual place of residence in the United States.

Counting the overseas deployed employees at their usual place of residence made them part of the U.S. resident population used for redistricting and allowed them to be included in all 2020 Census data products, rather than only being included in the apportionment counts. Less than 15 departments provided the U.S. Census Bureau an administrative records data file of employees deployed overseas. During the processing of the data, records for those employees deployed overseas, that matched to a stateside address in the Master Address File (MAF), were counted at their usual residence in the United States. The employees deployed overseas, whose address could not be matched to a stateside address in the MAF, were allocated to their home state and included in FACO tabulations for apportionment purposes.