🇺🇸 United States ZIP Code

STANDARD

37031

Castalian Springs

ZIP Code 37031 is a standard zip code serving Castalian Springs, Castalian Springs, Tennessee (TN), in Sumner County, United States. It has an estimated population of 3,712 with a median household income of $61,447. The area falls within the America/Chicago timezone.

Median Household Income vs. National Average

Location

Country: 🇺🇸 United States
State / Province: Tennessee (TN)
County: Sumner
City: Castalian Springs
Timezone: America/Chicago

Coordinates

Latitude: 36.380600
Longitude: -86.310700

Geographic Details

Land Area: 40.12 mi²
Water Area: 2.44 mi²
Population Density: 93.0 people per mi² (50th percentile)
Bounding Box: 36.447355°N, 36.299375°S, -86.209420°E, -86.362023°W

With 3,712 residents spread across 40.12 square miles, this area has a population density of 93.0 people per square mile.

Demographics

3,712

Population

50th percentile

$61,447

Median Income

75th percentile

$145,200

Median Home Value

55th percentile

40.12 mi²

Land Area

The median household income in 37031 is $61,447, and the median home value is $145,200. This places the area in the top 25% nationally for household income.

Housing

1,531

Total Units

1,395

Occupied Units

91.1%

Occupancy Rate

Similar ZIP Codes in Tennessee

ZIP codes with similar median household income in Tennessee.

37072

Goodlettsville

$53,138

38355

Medina

$69,457

37830

Oak Ridge

$54,663

37127

Murfreesboro

$61,051

37129

Murfreesboro

$62,295

38125

Memphis

$65,465

37149

Readyville

$53,828

37020

Bell Buckle

$53,471

Frequently Asked Questions

What information is available for each ZIP code?

Each ZIP code page shows city, state, county, geographic coordinates, timezone, population, median household income, median home value, housing units, land area, population density, commute time, educational attainment, area codes, and ZIP code type (Standard, PO Box, or Unique).

What are the different types of ZIP codes?

There are three types of ZIP codes: Standard (residential and commercial delivery areas), PO Box (assigned to post office box sections), and Unique (assigned to a single high-volume address like a government agency or large company). Standard ZIP codes are the most common.

How often is ZIP code data updated?

ZIP code assignments are updated quarterly by the USPS. Demographic data comes from the US Census Bureau's American Community Survey (ACS), which releases new 5-year estimates annually. ZipFYI updates its data to reflect the latest available information.

What is population density and why does it matter?

Population density measures the number of people per square mile in a ZIP code area. It helps identify urban vs. rural areas, affects real estate values, impacts service availability, and is used in market analysis. Dense urban ZIP codes may have 50,000+ people per square mile.

How are ZIP code boundaries determined?

ZIP code boundaries are determined by the USPS based on mail delivery routes, not political or geographic boundaries. They follow carrier routes and may cross city, county, or even state lines. Boundaries can change when the USPS reorganizes delivery operations.

What does median household income tell me about a ZIP code?

Median household income is the middle value when all household incomes in a ZIP code are sorted. Half of households earn more and half earn less. It is a better indicator of typical earnings than average income, which can be skewed by very high or very low outliers.