Geographic Terms and Concepts -
Geographic Names Information System Identifier

The Geographic Names Information System Identifier (GNIS ID) is a variable length, permanent, numeric identifier of up to ten digits in length that identifies each entity uniquely within the nation.  The GNIS is the new American National Standards Institute (ANSI) national standard code for several entity types.  Because each entity’s GNIS ID is permanent, it will not change if the entity changes its name or if creation of a new entity changes the alphabetic sort.  (Federal Information Processing Series codes are assigned based on the alphabetic sorting of entity names within a state and occasionally require changing codes to maintain the alphabetic sort.)  The GNIS IDs are assigned sequentially and stored in a right-justified, variablelength, numeric field without leading zeroes.  The GNIS now contains more than 2.6 million sequential records, thus no GNIS ID currently exceeds seven digits.  The Census Bureau portrays the GNIS ID in its data products as a fixed-width eight-character field with leading zeroes.

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