Census Data

US Census Data Skill

Query the US Census Bureau API for demographics, population, and economic data.

When to Use

• "What's the population of Texas?"
• "Show demographic breakdown by county"
• "Get median household income for California"
• "Compare poverty rates across states"

When NOT to Use

• Non-US data (use world-bank-data)
• Real-time economic data (use financial APIs)
• Historical pre-1790 data

Setup

Get a free API key at https://api.census.gov/data/key_signup.html

export CENSUS_API_KEY=your_key_here

API Base

https://api.census.gov/data/

Common Commands

ACS 5-Year Estimates (Most Used)

# Total population by state
curl -s "https://api.census.gov/data/2022/acs/acs5?get=NAME,B01001_001E&for=state:*&key=$CENSUS_API_KEY"

# Median household income by state
curl -s "https://api.census.gov/data/2022/acs/acs5?get=NAME,B19013_001E&for=state:*&key=$CENSUS_API_KEY"

# Population by county in California (state FIPS=06)
curl -s "https://api.census.gov/data/2022/acs/acs5?get=NAME,B01001_001E&for=county:*&in=state:06&key=$CENSUS_API_KEY"

# Poverty rate by state
curl -s "https://api.census.gov/data/2022/acs/acs5?get=NAME,B17001_001E,B17001_002E&for=state:*&key=$CENSUS_API_KEY"

Decennial Census

# 2020 total population by state
curl -s "https://api.census.gov/data/2020/dec/pl?get=NAME,P1_001N&for=state:*&key=$CENSUS_API_KEY"

Common Variables

Notes

• Free API key required for most queries
• ACS 5-year estimates are most reliable for small geographies
• FIPS codes identify states (e.g., 06=CA, 36=NY, 48=TX)
• Rate limit: 500 requests/day without key, more with key
• Variables list: https://api.census.gov/data/2022/acs/acs5/variables.html