Regional Codes ...
For statistical purposes, the US Census Bureau has divided the country into four Regions. Iditarod would have been located in Region #4 (the West Region).
In turn, the US Census Bureau has further divided each Region into Divisions. Iditarod would have been located in Division #9 (the Pacific Division).
The Office of Management and Budget (OMB) has created ten Federal Regions. Iditarod would have been located in Region X (Region 10).
Referenced GNIS Records ...
GNIS ID #1403697 (Name of Record: Iditarod)
Class: populated place
A place or area having clustered or scattered buildings and a permanent population (such as a city, settlement, town or village). The boundaries may or may not coincide with the perceived population.
A 'populated place' record may have a corresponding 'census' or 'civil' record. The information contained in the 'populated place' record applies only to the class and should not be confused with either the 'census' and 'civil' classes.
County: Yukon-Koyukuk (CA)
Map Name: Iditarod C-5
Lat: 62.5444444 Lon: -158.0952778 [Map]
Referenced FIPS Records ...
FIPS Code: 02/34640 (Place Name: Iditarod)
County: Yukon-Koyukuk (CA) (FIPS State/County: 02/290)
Identifies a populated place (ie- Iditarod) that is wholly or substantially located outside the boundaries of any incorporated place or CDP (Census Designated Place) that has an authoritative common name recognized by the U.S. Geological Survey (USGS).
GSA Code: 1072