census-mcp-server

Query U.S.

CommunityOnlineNo sign-inGlobalFreeRead-only

What it can do

  • Census List Datasets: Browse available Census Bureau datasets with their supported vintage years. Use as the starting point when the right dataset is unknown — ACS5, ACS1, population estimates, and de
  • Census List Geographies: List the geography levels available for a given Census dataset and year, along with the parent geographies each level requires. Use before querying to confirm that the target
  • Census Search Variables: Search Census variables by keyword across variable labels and concept groups. Returns variable codes with human-readable labels — use this to go from a concept like "median ho

What data it sees

Do you need an account

No: the server works without sign-in

Query U.S. Census Bureau data, variables, and geography via MCP.

How to connect

How to connect census-mcp-server to Claude

The server address to paste into Claude settings:

https://census-mcp-server--cyanheads.run.tools

  1. Open Claude (claude.ai or the desktop app).
  2. Go to Settings → Connectors.
  3. Click Add custom connector.
  4. Paste the server address copied below into Remote MCP server URL and click Add.
  5. In a chat, click + → Connectors and switch the new connector on.

Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

Authorization

After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

How to connect census-mcp-server to ChatGPT

The server address to paste into ChatGPT settings:

https://census-mcp-server--cyanheads.run.tools

  1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
  2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
  3. Open Settings → Connectors and click Create.
  4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
  5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
  6. In a new chat open + → Apps/Connectors and enable the connector.

OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

Authorization

On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

How to connect census-mcp-server to Cursor

The server address to paste into Cursor settings:

https://census-mcp-server--cyanheads.run.tools

Fastest: click Open in Cursor below and confirm the prompt.

Manually:

  1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
  2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
  3. Save the file. The server appears in the MCP list; authorize it there if asked.

Authorization

If the service needs sign-in, an authorize button appears next to the server in the MCP list.

Server tool list (7)

Raw names from tools/list. Only developers need these.

census_list_datasetsBrowse available Census Bureau datasets with their supported vintage years. Use as the starting point when the right dataset is unknown — ACS5, ACS1, population estimates, and decennial census serve different use cases. Pass the dataset_id value to the dataset parameter in other census tools.
census_list_geographiesList the geography levels available for a given Census dataset and year, along with the parent geographies each level requires. Use before querying to confirm that the target geography level exists — ACS1 omits many sub-state levels, and not all datasets support tracts or block groups. The geography_level values returned here are the valid inputs to the geography_level parameter in census_query_data and census_compare_geographies.
census_search_variablesSearch Census variables by keyword across variable labels and concept groups. Returns variable codes with human-readable labels — use this to go from a concept like "median household income" to the variable code B19013_001E needed for data queries. Returns both estimate (E suffix) and margin-of-error (M suffix) codes so you can request both. When total_matches exceeds the limit, narrow the query to see more specific results.
census_get_variableFetch full metadata for one or more Census variable codes — label, concept group, predicate type, universe, and margin-of-error sibling references. Use to confirm a variable code before building a query, or to look up what a known code means. Returns estimate_code and moe_code sibling references where applicable so you can request both without a separate search.
census_resolve_geographyResolve a place name or street address to Census FIPS identifiers (state, county, tract codes). Converts names like "King County, WA" or "Seattle, WA" to the FIPS codes required by census_query_data and census_compare_geographies. Use before querying when you have a place name rather than raw FIPS codes — state_fips maps to parent_fips and fips_summary maps to geography_fips in downstream tools.
census_query_dataQuery a Census dataset for one or more variables at a specific geography. Accepts FIPS codes for the target geography — use census_resolve_geography to convert place names to FIPS when needed. Labeled estimates and margin-of-error values are returned together. Suppression codes (geography too small, data not collected) are decoded into human-readable reasons rather than passed through as raw negative numbers. Pass geography_fips as "*" to return all geographies at the level within the parent.
census_compare_geographiesCompare one or more variables across multiple geographies at the same level — all counties in a state, all states nationally, or a named set of specific geographies. Results are sorted and ranked. Covers queries like "rank states by poverty rate", "compare median income across WA counties", or "which census tracts in King County have the highest renter rate." Omit within to compare all geographies nationally at the level. Suppressed values are decoded to human-readable labels rather than passed through as raw negative sentinels.