Spanish INE code
The official code identifying a Spanish province or municipality in the register kept by the Instituto Nacional de Estadistica.
INE assigns the codes for Spain's 52 provinces and roughly 8,100 municipalities.
The length states the tier. A province has two digits, from 01 Alava to 52 Melilla. A municipality has five: the province followed by three digits for the municipality within it, so A Arnoia is 32003 in Ourense 32. The leading zero is part of the code, and 01001 read as a number is no longer Alegria-Dulantzi.
The three-digit municipal part was assigned alphabetically within each province for the municipalities that existed at the end of 1970, and frozen since. Municipalities created later were given numbers starting at 9, so the codes are no longer in alphabetical order and a low number implies nothing about the name.
INE states that the codes of municipalities that have disappeared are not reused, with one exception: a municipality that is re-established recovers its original code. That makes the code a dependable key over time. INE also publishes a sixth check digit for detecting transcription errors; it is not part of the code, so a six-character value from a third party should be read as its first five.