I'm looking for the best/easiest way to programmatically grab the name of the US county a given US city resides in. It doesn't seem there's a straightforward API available for such a (seemingly simple) task?
5 Answers
1) Cities span counties
2) Zips span both cities and counties, not even on the same lines
Any solution that uses zip as an intermediary is going to corrupt your data (and no, "zip+4" won't usually fix it). You will find that a city-to-zip-to-county data map (#2) has a larger number of city-to-county matches than the more accurate model (#1)--these are all bad matches.
What you're looking for is free census data. The Federal Information Processing Standards (FIPS) dataset you need is called "2010 ANSI Codes for Places": https://www.census.gov/geographies/reference-files/time-series/geo/name-lookup-tables.2010.html
Census "places" are the "cities" for our question. These files map "places" to one or more county.
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