Census.gov

How to Use This API

1. Get Population for All States

This query retrieves name and total population for every US state from the 2020 Census:

https://api.census.gov/data/2020/dec/pl?get=NAME,P1_001N&for=state:*

get specifies the columns to return. P1_001N is the total population. for=state:* means all states.

2. Population for a Specific County

https://api.census.gov/data/2020/dec/pl?get=NAME,P1_001N&for=county:037&in=state:06

Returns data for Los Angeles County, California (state FIPS 06, county FIPS 037).

3. JavaScript — State Population Dashboard

fetch('https://api.census.gov/data/2020/dec/pl?get=NAME,P1_001N&for=state:*')
  .then(r => r.json())
  .then(data => {
    // First row is headers
    const headers = data[0];
    const rows = data.slice(1).map(r => ({
      state: r[0],
      population: parseInt(r[1]),
      fips: r[2]
    }));
    rows.sort((a, b) => b.population - a.population);
    console.log('Most populous states:');
    rows.slice(0, 10).forEach(s =>
      console.log(`${s.state}: ${s.population.toLocaleString()}`));
  });

4. Python — ACS Median Income Query

import requests

# American Community Survey 2022 median household income by state
r = requests.get(
  'https://api.census.gov/data/2022/acs/acs1/subject',
  params={'get': 'NAME,S1901_C01_001E', 'for': 'state:*'}
)
if r.status_code == 200:
    rows = r.json()
    for row in rows[1:10]:  # Skip header
        print(f"{row[0]}: ${float(row[1]):,.0f}")