This is the CodeSystem that contains all the codes in Federal Information Processing Standards Publication: Codes for the Identification of the States, the District of Columbia and the Outlying Areas of the United States, and Associated Areas (FIPS 5-2) (http://terminology.hl7.org/CodeSystem/FIPS52) and Federal Information Processing Standards Publication: Codes for the Identification of the States, the District of Columbia and the Outlying Areas of the United States, and Associated Areas (FIPS 5-2) (http://terminology.hl7.org/CodeSystem/FIPS52). E.g. what you have to deal with if you get resources containing codes in either of them