Census API Server

Access U.S. Census Bureau data including demographics, population, income, housing, and more.

Data Available

• American Community Survey (ACS) - Detailed demographic and socioeconomic data
  • 1-year estimates (acs/acs1) - Areas with 65,000+ population
  • 5-year estimates (acs/acs5) - All areas, more reliable for small populations
• Decennial Census (dec/pl) - Official population counts every 10 years
• Economic Census - Business and industry statistics
• Population Estimates - Annual population estimates between censuses

Setup

1. Get a free API key at: https://api.census.gov/data/key_signup.html
2. Add to your MCP config:

{
  "census": {
    "command": "node",
    "args": ["/path/to/census-api/dist/index.js"],
    "env": {
      "CENSUS_API_KEY": "your-api-key"
    }
  }
}

Tools

query

Fetch Census data with full control over variables and geography.

Parameter	Required	Description
year	Yes	Data year (e.g., "2022")
dataset	Yes	Dataset path (e.g., "acs/acs1", "acs/acs5", "dec/pl")
variables	Yes	Comma-separated variable codes (e.g., "NAME,B19013_001E")
forClause	Yes	Geography to fetch (e.g., "state:", "county:", "state:06")
inClause	No	Parent geography for nested queries (e.g., "state:06" when getting counties)

Example: Get median household income for all states

year: "2022"
dataset: "acs/acs5"
variables: "NAME,B19013_001E"
forClause: "state:*"

list_datasets

List available Census datasets for a given year.

Parameter	Required	Description
year	Yes	Year to list datasets for

list_variables

Search for variables in a dataset. Useful for finding the right variable codes.

Parameter	Required	Description
year	Yes	Data year
dataset	Yes	Dataset path
search	No	Keyword to filter (e.g., "income", "population")
limit	No	Max results (default 50)

Example: Find income-related variables

year: "2022"
dataset: "acs/acs5"
search: "income"

list_geographies

List available geographic levels for a dataset.

Parameter	Required	Description
year	Yes	Data year
dataset	Yes	Dataset path

get_fips

Get FIPS codes for states, counties, or other geographies.

Parameter	Required	Description
year	Yes	Data year
dataset	Yes	Dataset path
geography	Yes	Level (e.g., "state", "county")
inClause	No	Parent geography filter

Example: Get all county FIPS codes in California

year: "2022"
dataset: "acs/acs5"
geography: "county"
inClause: "state:06"

Common Variables

Variable	Description
B01003_001E	Total Population
B19013_001E	Median Household Income
B25077_001E	Median Home Value
B23025_005E	Unemployed Population
B15003_022E	Bachelor's Degree holders
B25064_001E	Median Gross Rent

Rate Limits

• No strict rate limit with API key
• Without key: 500 requests/day

Documentation

• API Documentation: https://www.census.gov/data/developers/guidance.html
• Variable Search: https://api.census.gov/data.html