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Quick Answer: A Census GeoID is a numeric code that uniquely identifies geographic areas, ranging from 2-40 digits depending on the granularity needed.
GeoIDs, also called FIPS Codes, are a unique identifier for a geographic area, from as small as a few blocks to as large as a metropoitan area or state, and are often used to join government datasets. For example, if you have a list of addresses and want to find the average household income for those neighborhoods, you'll need the GeoIDs for the addresses and the GeoIDs for the household income data from the Census. According to the Census Bureau, "GEOIDs are numeric codes that uniquely identify all administrative/legal and statistical geographic areas for which the Census Bureau tabulates data."
At a practical level, GeoIDs (also called FIPS Codes) are different combinations of those Census identifiers. Depending on the data you're working with, you might need a different length of GeoID.
GeoIDs, or FIPS codes, can be up to 40 digits. The more digits there are, the more granular of a measurement it is.
Geocodio returns FIPS codes, and from those FIPS codes, you can create the GeoID you need based on the required number of digits.
Quick Answer: A GeoID/FIPS Code is made up of a combination of FIPS Codes from multiple geographic levels. For example, it might combine the State, County, and Tract FIPS codes to create one 11-digit FIPS code.
GeoIDs are built based on a combination of Census FIPS codes, which are unique identifiers for different levels of geographic data. The largest geographic area covered by a FIPS code is the State, and the smallest is the Block. Here's the order of FIPS codes, in declining order of size:
Geocodio will return these FIPS codes levels to you, and then you can build the GeoID you need.
Quick answer: The most common GeoID/FIPS Code lengths you'll find across government datasets are 11, 12, and 15 digits. An 11-digit FIPS code combines the state, county, and tract FIPS codes. A 12-digit FIPS code combines the state, county, tract, and block group FIPS codes. A 15-digit FIPS code combines the state, county, tract, and block FIPS codes.
Let's use 1600 Pennsylvania Avenue, Washington DC as an example:
| If you have/need a GeoID of this length... | ...it translates to this combination of FIPS codes | Example GeoID | Geocodio Results to Use |
|---|---|---|---|
| 2 digit GeoID | State | 11 | State FIPS |
| 5 digit GeoID | State + County | 11001 | County FIPS (i.e. concatenated State + County) |
| 11 digit GeoID | State + County + Tract | 11001006802 | combine County FIPS + Tract Code; pre-concatenated for spreadsheet uploads as "Full FIPS (tract)" |
| 12 digit GeoID | State + County + Tract + Block Group | 110010068022 | combine County FIPS + Tract Code + Block Group |
| 15 digit GeoID | State + County + Tract + Block | 110010068022012 | combine County FIPS + Tract Code + Block Code; pre-concatenated for spreadsheet uploads as "Full FIPS (block)" |
Quick Answer: Yes. There are a variety of tools you can use to look up GeoIDs/FIPS Codes in bulk, such as the Census Bureau Geocoder and Geocodio.
Whatever tool you use, you need to make sure that it returns the Census vintage for the data and that the Census vintage matches the dataset you're trying to join data with. The Census Geocoder can be used for batches of up to 10,000 address per file, but only Census years 2010 and 2017-present are available. With Geocodio, you can look up thousands or even millions of GeoIDs in one batch and with one click, add historical (past-year) Census FIPS codes, blocks, and tracts to addresses or coordinates.
Geocodio provides Census GeoIDs/FIPS Codes for the 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, and 2024 Census years.
Geocodio's Census data append includes:
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Yes, they can. The Census updates geographies for legal areas (cities, towns, etc) every year, and boundaries for statistical areas (unicorporated areas, metropolitan areas, etc) So when you're working with GeoIDs/FIPS Codes, you need to make sure that the datasets you're joining are using the same Census year ("vintage"). The datasets should give the Census year that they're using.
GeoIDs are required in a variety of situations:
GeoIDs are also helpful when conducting research that uses government data. For example, the following academic research papers used FIPS codes from Geocodio:
Note: Please note that "geoid" has a different meaning in a geological sense. According to the US Geological Society, a geoid in a geological sense is "A geoid is the irregular-shaped “ball” that scientists use to more accurately calculate depths of earthquakes, or any other deep object beneath the earth’s surface." This is not the geoid that Geocodio provides or the Census refers to.