{
  "zip": "37031",
  "type": "standard",
  "type_source": "inferred",
  "city": "Castalian Springs",
  "other_place_names": [
    "Hartsville/Trousdale County"
  ],
  "state": "TN",
  "state_name": "Tennessee",
  "county": {
    "fips": "47165",
    "name": "Sumner County",
    "short_name": "Sumner"
  },
  "counties": [
    {
      "county_fips": "47165",
      "name": "Sumner County",
      "short_name": "Sumner",
      "weight": 0.7818,
      "basis": "land_area"
    },
    {
      "county_fips": "47169",
      "name": "Trousdale County",
      "short_name": "Trousdale",
      "weight": 0.2182,
      "basis": "land_area"
    }
  ],
  "location": {
    "lat": 36.377463,
    "lng": -86.301172,
    "source": "gazetteer_internal_point",
    "timezone": "America/Chicago"
  },
  "is_zcta": true,
  "parent_zcta": null,
  "metro": {
    "cbsa_code": "34980",
    "name": "Nashville-Davidson--Murfreesboro--Franklin, TN",
    "type": "metro",
    "csa_code": "400",
    "csa_name": "Nashville-Davidson--Murfreesboro, TN"
  },
  "demographics": {
    "population": 3926,
    "households": 1707,
    "housing_units": 1804,
    "median_age": 53.5,
    "median_household_income": 98114,
    "median_home_value": 352600,
    "median_rent": null,
    "pct_bachelors_plus": 21.2,
    "mean_commute_min": 29.1,
    "density_per_sqmi": 102.6
  },
  "business": {
    "establishments": 38,
    "employees": 187,
    "annual_payroll_thousands": 7156
  },
  "tax": {
    "irs_returns": 2160,
    "irs_agi_thousands": 164224
  },
  "area": {
    "land_sqmi": 38.253,
    "water_sqmi": 1.757
  },
  "nearest_zips": [
    {
      "zip": "37087",
      "miles": 8,
      "city": "Lebanon",
      "state": "TN"
    },
    {
      "zip": "37066",
      "miles": 8.7,
      "city": "Gallatin",
      "state": "TN"
    },
    {
      "zip": "37074",
      "miles": 8.9,
      "city": "Hartsville",
      "state": "TN"
    },
    {
      "zip": "37022",
      "miles": 9.5,
      "city": "Bethpage",
      "state": "TN"
    },
    {
      "zip": "37088",
      "miles": 11.7,
      "city": "Lebanon",
      "state": "TN"
    },
    {
      "zip": "37151",
      "miles": 15.1,
      "city": "Riddleton",
      "state": "TN"
    },
    {
      "zip": "37071",
      "miles": 15.3,
      "city": "Gladeville",
      "state": "TN"
    },
    {
      "zip": "37136",
      "miles": 15.3,
      "city": "Norene",
      "state": "TN"
    },
    {
      "zip": "37057",
      "miles": 15.3,
      "city": "Dixon Springs",
      "state": "TN"
    },
    {
      "zip": "37186",
      "miles": 15.8,
      "city": "Westmoreland",
      "state": "TN"
    }
  ],
  "release": "2026-10-12",
  "attribution": {
    "source": "zipcodes.pro",
    "url": "https://zipcodes.pro/zip/37031",
    "sources_url": "https://zipcodes.pro/sources",
    "license": "Facts derived from US public-domain data (Census, IRS) and GeoNames (CC BY 4.0). Attribution appreciated: zipcodes.pro",
    "note": "A null value means the source did not publish that figure for this ZIP code. It does not mean zero."
  }
}