US Address Geocoder & Census Tract Lookup

Batch geocode US addresses to latitude and longitude and get the census geographies for each one in the same row: state and county FIPS, county name, city/place, census tract, block group, census block, ZIP Code Tabulation Area (ZCTA), metro area (CBSA), combined statistical area, congressional district, state senate and house districts, school district, urban area. Works in reverse too: give lat, lon points and get the same geographies. Use it as a free-data geocoding API, a census tract lookup, a FIPS code lookup, or an address to congressional district tool.

Data comes from the official US Census Bureau Geocoder (geocoding.geo.census.gov, public domain, no API key). Results join directly to Census/ACS tables, HMDA and CRA files, opportunity-zone and LIHTC lists, FEMA and HUD datasets, because they use the same GEOIDs.

Why this one

• Unmatched addresses are free. You pay only for addresses (or points) that match. Unmatched rows are still saved so you can fix them.
• Every geography in one pass: no second lookup for tracts, FIPS or districts.
• No Google Maps key, no quota, no ToS limits on storing results (Census data is public domain).

Who uses it

Real-estate, mortgage and insurance analysts (tract-level risk and fair-lending files), CRM and lead-list cleanup (lat/lon + county for routing), political and advocacy groups (address → congressional and legislative district), public-health and academic researchers (address → tract → ACS demographics), retail site selection.

Input examples

Batch of addresses:

{"addresses": ["233 S Wacker Dr, Chicago, IL 60606", "350 5th Ave, New York, NY 10118"]}

Structured records from a spreadsheet:

{"addressRecords": [{"street": "400 Broad St", "city": "Seattle", "state": "WA", "zip": "98109"}]}

Reverse geocode points to tract and district:

{"coordinates": ["41.8789, -87.6359", "34.0522, -118.2437"]}

2020 Census geographies (for decennial-census joins):

{"addresses": ["1600 Pennsylvania Ave NW, Washington, DC 20500"], "benchmark": "Public_AR_Census2020", "vintage": "Census2020_Census2020"}

Output fields

inputIndex, input, inputType (address|coordinates), matched, matchedAddress, latitude, longitude, streetNumberRange, matchedCity, matchedState, matchedZip, tigerLineId, side, stateFips, stateCode, stateName, countyFips, countyName, placeName, placeGeoid, countySubdivision, censusTract, censusTractName, blockGroup, censusBlock, zcta, congressionalDistrict, congressionalDistrictGeoid, stateSenateDistrict, stateHouseDistrict, metroArea, cbsaCode, combinedStatisticalArea, schoolDistrict, urbanArea, alternativeMatches, note, benchmark, retrievedAt

Real samples are in samples/.

Accuracy notes

The Census Geocoder interpolates along TIGER street address ranges, so the point sits on the street segment, not the rooftop. It covers the 50 states, DC and Puerto Rico. PO boxes, rural routes and brand-new streets may not match. Adding the ZIP code helps. Throughput is roughly 10-25 addresses per second.

Pricing

Pay per matched address or point (address-geocoded event). Unmatched inputs are free. Cap spend with Max results.

Notes

Not affiliated with the US Census Bureau. This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau.