How to Find Age Demographics by ZIP Code

Median age at the ZIP code level has bigger variances than almost any other census statistic. One ZIP in Orange County, California has a median age of 74.9. One in Ocean County, New Jersey has a median age of 18.2, white both hold more than 10,000 people.

Here's how to look the figure up for any ZIP, and what the extremes look like once you do.

Where to find it

Every ZIP code page on this site carries median age along with the share of residents under 18 and the share 65 and older. That last pair matters more than the median for most questions, because a median of 40 can describe a place full of 40-year-olds or a place split evenly between children and retirees.

The Census Bureau publishes the same figures through the American Community Survey. The variable is B01002_001E for median age, and ZIP-level data is only available in the five-year files, which pool 60 months of responses. If you want to pull it yourself, the codes are explained in how to read census table codes.

The Bureau does not publish data for postal ZIP codes. It publishes ZIP Code Tabulation Areas, which approximate them from census blocks, so a ZCTA and the ZIP your mail carrier uses can differ at the edges.

The oldest ZIP codes

ZIP codes with at least 10,000 residents.

Three of the six are in Arizona and two are in Sumter County, Florida. These are age-restricted retirement developments, which is the only way a place of 25,000 or more people reaches a median age in the seventies. Sumter County's two ZIPs hold 55,424 and 28,549 residents between them, so this isn't a handful of retirees in a small town.

The youngest ZIP codes

Five of these six hold between 10,000 and 15,000 people and sit in counties containing large public universities. A ZIP that covers dormitories will post a median age around 19 and a household income that looks like poverty, which is why student areas distort both rankings. The same distortion shows up in cities with the most unmarried people, where campus towns crowd the top until you set a population floor.

The exception is the first one. 08701 in Ocean County, New Jersey holds 139,149 residents, roughly ten times the others, and no campus accounts for a population that size. A median age of 18.2 across 139,000 people means the place has an unusually high birth rate and very large households, which is a different demographic story from a dorm ZIP.

Why the under-18 and 65-plus shares matter more

Median age compresses a distribution into one number and loses the shape. A ZIP at 40 could be mostly middle-aged, or it could be half children and half grandparents with few people in between, and the two need completely different schools, housing and services. Both share figures are on every ZIP page for that reason.

For the same measure at larger geographies, see the oldest and youngest states and the oldest and youngest cities, or the national aging trend in America's record median age.

Sources

Median age and population figures are from the U.S. Census Bureau American Community Survey five-year estimates for ZIP Code Tabulation Areas. County assignments follow the Census Bureau's ZCTA-to-county relationship file.