Free Online Reverse Geocoding Web Service

https://geoservices.tamu.edu/Services/CensusIntersection/WebService/v04_01/HTTP/default.aspx

Parameter	Required	Description	Example	Possible Values
apiKey	true	click here for your API key	api-key-value	text string
version	true	the version of the parser to use	4.01	4.01
censusYear	true	the requested year of census data	2010	1990, 2000, 2010
lat	true	the latitude of the input coordinate	34.0726207996348	double
lon	true	the longitude of the input coordinate	-118.397965182076	double
s	false	the abbreviation of the state of the input	CA	text string
format	false	output format	csv	csv, tsv, xml, json
notStore	false	indicates if the transaction details should not be historically stored in your account	true	true, false

Position	Field	Required	Description	Possible Values
0	Query Status Code	true	Result code	See list
1	API Version	true	Vesion of the API used	4.01
2	Transaction Id	true	Query Id	Unique Id
3	Census Year	true	Year of the census data returned	NineteenNinety, TwoThousand, TwoThousandTen, TwoThousandTwenty, AllAvailable
4	Census Block	true	Census block value for the output point
5	Census Block Group	true	Census block group value for the output point
6	Census Tract	true	Census tract value for the output point
7	Census Place Fips	true	Census place fips value for the output point
8	Census MCD Fips	true	Census minor civil division fips value for the output point
9	Census MSA Fips	true	Census metropolitan statistical area fips value for the output point
10	Census CBSA Fips	true	Census core base statistical area fips value for the output point
11	Census CBSA Micro	true	Census core base statistical area micropolitan flag for the output point
12	Census MetDiv Fips	true	Census metropolitan division fips value for the output point
13	Census County Fips	true	Census county fips value for the output point
14	Census State Fips	true	Census state fips value for the output point
15	Time Taken	true	Processing time	Milliseconds

Example 1 - 34.0726207996348, -118.397965182076, CA (CSV, 2010)
Example 2 - 34.0726207996348, -118.397965182076, CA (XML, 2000)
Example 3 - 34.0726207996348, -118.397965182076, CA (JSON, 2010)
Example 4 - 34.0726207996348, -118.397965182076 (CSV, 2010)
Example 5 - 34.0726207996348, -118.397965182076 (XML, 2010)
Example 6 - 34.0726207996348, -118.397965182076 (XML, all available years)
Example 7 - 34.0726207996348, -118.397965182076 (CSV, all available years - will return 3 result rows [1990, 2000, 2010])
Example 8 - 34.0726207996348, -118.397965182076 (JSON, all available years - will return 3 result rows [1990, 2000, 2010])

Census Intersection Web Service - HTTP API