Boundary Atlas compared: Census Geocoder, HUD crosswalk, Cicero, Geocodio and others
Boundary Atlas is the only one of these that combines current voting precincts, population-weighted crosswalks between ZIPs, cities, counties and districts, GeoJSON boundaries and Canada, through a free MCP server with no key. The others are better for some jobs: elected officials' names (Cicero, Open States), geocoding (Census Geocoder, Geocodio) and real USPS ZIPs (HUD).
| What it is | Precincts | Population-weighted crosswalk | GeoJSON boundaries | Canada | MCP access | Published price | Best for | |
|---|---|---|---|---|---|---|---|---|
| Boundary Atlas | MCP server + site: cities, ZIPs, counties, towns, districts, precincts, Canadian ridings | Yes, current official files for ~92% of the US | Yes (2020 population) | Yes | Yes: ridings, polling divisions, provincial districts | Yes, remote, no key | Free (60 requests/min per IP) | Agents that need lookups, crosswalks and maps together |
| U.S. Census Geocoder | Free address and coordinate lookup to Census geographies, including 120th Congress and 2026 state legislative districts | No | No | No | No | Community wrappers | Free | Geocoding addresses; official Census answers; tracts and blocks |
| Census TIGER/Line files | Raw shapefiles for every Census geography, including 2026 congressional districts | No | No | No (shapefile, geodatabase) | No | Community wrappers | Free | Complete official geometry: tracts, school districts, metros |
| HUD-USPS ZIP crosswalk | Quarterly files mapping USPS ZIPs to tracts, counties, metros and congressional districts | No | Address-based ratios (not population) | No | No | No | Free (account and token) | Real USPS ZIPs, updated quarterly |
| Cicero (Melissa) | Paid API: districts and elected officials, including local, school and judicial | Not listed | ZIP-to-district files (custom quote) | No (map images) | Yes | None found | $298 for 5,000 credits up to $8,848 for 1M | Elected officials' names and local districts |
| Geocodio | Geocoding with congressional and legislative district appends, incl. 120th Congress maps | Not listed | No | Not listed | Yes: federal and provincial ridings | Third-party wrappers | 2,500 lookups/day free, then paid | Geocoding addresses with district fields in one call |
| zip-codes.com | ZIP and postal-code database and API with district fields; official remote MCP server | No | Radius overlap only | Not stated | Yes: postal codes | Yes, remote, keyless demo | 2,500 credits/day free; $49–$499/month | USPS ZIP attributes, school districts |
| Smarty | Address validation and geocoding with congressional district | No | No | No | No | Yes, first-party (needs an account) | From $125/month | Validating and standardizing addresses |
| Open States / Represent | Legislators by location (US states); Canadian representatives and ward boundaries | No | Represent: postal-code concordances | Represent: yes | Represent: yes | Community servers | Free tiers | Who represents a location (names, contacts) |
From each product's own pages, checked November 6, 2026. Prices and features change; follow the links for current terms. Spot an error? It'll be fixed.
When to use something else
- You need elected officials' names: Cicero, Open States (US state legislators) or Represent (Canada). Boundary Atlas has districts, not people.
- You need to geocode addresses: The Census Geocoder (free) or Geocodio. Boundary Atlas uses the Census Geocoder for its own address lookup.
- You need real USPS ZIPs, updated quarterly: The HUD-USPS crosswalk. Boundary Atlas uses Census ZCTAs, which approximate ZIPs and are fixed for the decade.
- You need tracts, school districts or metro areas: TIGER/Line files, the Census Geocoder or zip-codes.com. Boundary Atlas doesn't have those yet.
- You need a contract or SLA: A paid provider. Boundary Atlas is free and best-effort.
Questions
Is there a free alternative to Cicero for district lookups?
For districts (not officials), yes: the Census Geocoder returns the 2026 congressional and state legislative districts for an address, and Boundary Atlas adds precincts, cities, population-weighted ZIP crosswalks, GeoJSON and Canada through a free MCP server. For officials' names, use Open States or Represent.
What replaced the Google Civic Information API's representatives lookup?
Google announced the shutdown of its representatives endpoint in 2024, effective April 2025. For districts, use the Census Geocoder or Boundary Atlas; for elected officials, Open States, Represent (Canada) or Cicero.
Census Geocoder or Boundary Atlas?
Use the Census Geocoder to turn an address into coordinates and official Census geographies. Use Boundary Atlas when you also need precincts, cities with shares, ZIP crosswalks, polygons or Canada, or want an agent to do it over MCP.
HUD crosswalk or Boundary Atlas for ZIP to county?
HUD weights by USPS addresses and uses real ZIPs, updated quarterly. Boundary Atlas weights by 2020 population, uses Census ZCTAs, and also crosses to cities, towns, precincts and the 2026 districts. For business addresses, HUD's business ratio may fit better.