Largest ZIP Codes

The United States has over 42,000 active ZIP codes, ranging from tiny urban postal zones covering a few city blocks to massive rural ZIP codes spanning hundreds of square miles. Understanding which ZIP codes are the largest — by population, by geographic area, or by housing unit count — provides essential insight for market analysis, resource planning, political districting, and geographic research.

Largest ZIP Codes by Population

Population within a ZIP code is measured using ZIP Code Tabulation Area (ZCTA) data from the US Census Bureau American Community Survey (ACS). The most populous ZIP codes in the United States cluster in two distinct patterns: dense urban cores in major metropolitan areas, and rapidly growing suburban corridors in Sun Belt cities.

The very top of the population ranking is dominated by ZIP codes in New York City (particularly Queens and Brooklyn, where ZCTAs cover dense multi-family housing at extraordinary densities), Houston's western suburbs, Chicago's south and southwest sides, and fast-growing suburban Texas cities like Katy and El Paso. The most populous ZIP codes consistently exceed 100,000 residents — more people than many small US cities. ZIP 79936 in El Paso, Texas, has ranked among the most populous in the country with approximately 110,000 residents in a ZIP code that covers growing residential suburbs near Fort Bliss.

Why Queens, New York ZIP Codes Dominate Population Lists

Queens is the most ethnically diverse urban area in the world and one of the most densely populated. ZIP codes like 11368 (Corona / Jackson Heights area) and 11385 (Ridgewood / Glendale) pack over 100,000 residents into a few square miles of dense low-rise and mid-rise apartment buildings. The combination of high residential density, multi-family housing predominance, and large average household sizes in immigrant communities drives these extraordinary population figures.

Formula: ZIP Code Population Density

Population Density (per sq mi) = Total Population ÷ Land Area (sq mi)

A ZIP code with 100,000 residents covering 2 square miles has a density of 50,000 per sq mi — comparable to the densest urban neighborhoods in Asia. The same population over 500 square miles = 200 per sq mi, typical of a low-density suburb. Density is the contextualizing metric that makes raw population counts meaningful for planning and analysis.

Largest ZIP Codes by Geographic Area

Geographic size and population are often inversely correlated. The largest ZIP codes by land area are almost exclusively in the rural West. Parts of Alaska, Nevada, Wyoming, and Montana have ZIP codes spanning thousands of square miles — sometimes larger than entire eastern US states. These massive rural ZIPs often correspond to a single rural delivery route serving scattered ranches, mines, or small communities across vast wilderness territory.

The largest ZIP codes by area are functionally different entities from their urban counterparts. A 10,000-square-mile rural Alaska ZIP might have 500 residents served by a once-weekly mail plane. A 0.1-square-mile Manhattan ZIP might have 30,000 residents served by daily multi-carrier delivery. Both are called ZIP codes, but they represent fundamentally different postal and demographic realities.

Largest ZIP Codes by Housing Unit Count

Housing units (as distinct from population) is the metric most relevant for utilities, mail volume estimation, and residential service planning. A ZIP code with many small households may have more housing units than a ZIP with fewer but larger households. Census ACS ZCTA data provides housing unit counts including total units, occupied units, and vacant units (with vacancy broken down by seasonal, for rent, for sale, and other vacant categories).

Business Applications: Territory Design and Market Sizing

Understanding ZIP code size is critical for territory design. A sales territory defined by 5 ZIP codes might represent 5 dense urban blocks or 5 counties worth of rural territory — dramatically different workloads for a field representative. Combining population data with geographic area gives you population density per ZIP, a more actionable metric for territory balancing. Target population density, not raw ZIP count, when designing equitable territories.

For logistics, large geographic ZIPs mean longer last-mile delivery routes. A single ZIP code in rural Montana might require 4+ hours of driving to complete all deliveries, while an urban ZIP might have 200 stops within a 1-mile radius. Last-mile delivery cost per package is highly correlated with geographic ZIP size.

Census Data and ZIP Code Demographics

The Census Bureau's ACS releases ZIP-level demographic data including total population, number of housing units, median household income, age distribution, educational attainment, and racial and ethnic composition. This ZIP-level demographic data is publicly available through the Census Bureau's American FactFinder (now data.census.gov) and forms the foundation of ZIP code population analysis tools. Population figures in our Largest ZIP Codes tool use the most recent ACS 5-year estimates, providing the most statistically reliable ZIP-level population data available.