Posted By: deya
I was thinking the same thing. I used to live in La Jolla when I was attending school nearby... Everyone writes La Jolla on their mail as if it were it's own city but it isn't officially.
Regarding mail, it is in a way. Anyone who has paid attention realizes that ZIP codes
for the City of San Diego start with "921" except the LaJolla "neighborhood, which
follows the "920" ZIP codes of most of the other cities in San Diego County. (Some
southern and eastern cities were changed to "919" about 15 years ago because of
the increasing population in the county.) ZIPs for UCSD are 92092 and 92093, follwing
the pattern for the LaJolla neighborhood, in which the campus is located.
What is not answered by the Wikipedia article linked below is "why" La Jolla was given a county zip of "920". The then US Post Office Department instituted ZIP codes in 1963, when La Jolla resident Bob Wilson was San Diego County's sole US Representative in Congress. While I have not seen it in writing, the generally accepted history is that the PO assigned La Jolla a "920" ZIP so that residents could continue to use "La Jolla" on their mail rather than the less prestigous "San Diego".
(Note: in the photo below "92037" is set off to the right because it was added long after the building was constructed.)
As with TER ratings, numbers can be very significant.