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Address → Census block API

Find a US address's Census block — in one API call

AddressCanvas returns the 15-digit 2020 Census block GEOID and county FIPS where available. Derive tract and block group from the block GEOID. In our serving-index snapshot, 99.9% of indexed addresses carry a block and 83.9% have rooftop placement. One POST, one JSON response, results you can store.

Get 5,000 free geocodes/month

The problem

Demographic enrichment, public-health research, and geographic analysis need addresses tied to Census geographies. That can mean using the Census Bureau's geocoder, maintaining a PostGIS + TIGER pipeline, or joining a geocoder's output to Census boundaries yourself. Compare the options on our Census Geocoder comparison page.

The fix

A block GEOID contains state (2) + county (3) + tract (6) + block (4). When censusBlock is present, its first 11 digits identify the tract and its first 12 the block group. County FIPS is returned separately in fips. Keep the returned GEOID in your warehouse indefinitely.

curl -X POST "https://addresscanvas.com/api/v1/geocode" \
  -H "X-API-Key: gck_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{"address": "1600 Pennsylvania Ave NW, Washington, DC 20500"}'
{
  "standardizedAddress": "1600 PENNSYLVANIA AVE NW, WASHINGTON, DC 20500",
  "lat": 38.89594,
  "lon": -77.037419,
  "fips": "11001",
  "censusBlock": "110019800001034",
  "locationCode": "ROOFTOP"
}

Why AddressCanvas for Census geocoding

  • Census block on 99.9% of indexed addresses. Included where available, without a separate charge or call.
  • Placement is labeled. Inspect locationCode to distinguish rooftop, parcel, and lower-precision results.
  • You own the output. No caching restrictions — store GEOIDs in your warehouse indefinitely.
  • Enrich in the same place. /api/v1/demographics returns 2020 Census + ACS data for the same address on credits.

Geography with match provenance

Geographic analysis needs reproducible geography and a clear record of how each point was resolved. Inspect matchCode and pointReason, and handle missing GEOIDs explicitly. Informational geocoding for analysis and enrichment — confirm suitability for your specific regulatory filing requirements and follow our terms.

Start free — Census block included

5,000 requests/month, no card. A matched address may carry a block GEOID; city- and ZIP-level fallbacks do not.

Get your API key — 150 free credits