The Most Populated ZIP Codes in the US and Around the World

Behind each ZIP code lies a wealth of insights—clusters of people, patterns of movement, and untapped opportunities. Take ZIP codes like 11226 in Brooklyn or 11373 in Queens—each with populations over 100,000. That’s more than the entire population of many small cities globally!

What’s the real value here? By digging into these high-density ZIP codes, you can find patterns that help you optimize delivery routes, choose new warehouse locations, or even target new markets.

In this article, we’ll break down why these ZIP codes matter, from housing demand to economic activity, and how you can use this data to make smarter decisions.

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The List of Top 5 Most Populated ZIP Codes in the US

Examples of the Most Populated ZIP Codes in the US

In this section, we only look at ZIP codes for more than 50,000 people to minimize bias of very small zip codes. Get ready to explore neighborhoods packed with history, culture, and—well—people!

5. Upper West Side, Manhattan, NY

• ZIP Code: 10025
• Population: 98,489
• Density: 42,430 people per square km

Kicking off our list is the heart of Manhattan’s Upper West Side. With nearly 100,000 people packed into just over 2 square kilometers, this area is a marketer’s dream. Think of the foot traffic! From young professionals to families, this diverse neighborhood is prime real estate for businesses looking to capture a slice of the Big Apple pie.

The Upper West Side is known for its cultural institutions like the Lincoln Center and the American Museum of Natural History. It’s a haven for book lovers with its many bookstores, and foodies flock to its gourmet shops and famous restaurants. If you’re in the business of culture, or high-end retail, this is your spot.

4. Flatbush, Brooklyn, NY

• ZIP Code: 11226
• Population: 109,329
• Density: 29,860 people per square km

Brooklyn is well represented by Flatbush. This melting pot of cultures is home to over 109,000 people. While it’s not as tightly packed as some Manhattan spots, the sheer number of potential customers makes this a hotspot for businesses. From Caribbean cuisine to trendy cafes, there’s room for every niche in this bustling borough.

Flatbush is a neighborhood in transition, blending its Caribbean and African American roots with an influx of young professionals. It’s home to the historic Kings Theatre and close to Prospect Park. Businesses that can bridge traditional and modern tastes – think fusion restaurants or tech-savvy services for a diverse clientele – could thrive here.

3. Elmhurst, Queens, NY

• ZIP Code: 11373
• Population: 104,139
• Density: 26,280 people per square km

Queens gets in on the action with Elmhurst. This neighborhood is known for its incredible diversity, which means one thing for businesses: opportunity! With over 104,000 residents from all walks of life, it’s a goldmine for companies looking to test new products or services across various demographics.

Elmhurst is often called one of the most diverse neighborhoods in the world. It’s a hub for Asian cuisine, with everything from dim sum palaces to Thai street food. The Queens Center Mall is a major draw. If you’re in the import/export business, Elmhurst should be on your radar.

2. Lower East Side, Manhattan, NY

• ZIP Code: 10002
• Population: 85,387
• Density: 34,972 people per square km

The Lower East Side comes in hot. This historic neighborhood has transformed into a hipster haven, packed with nearly 85,400 residents. For businesses, this means a perfect blend of old-school charm and new-age cool. Whether you’re a major retailer looking to launch a trendy flagship store or opening a tech startup, this ZIP code’s got the crowd you’re after.

Once a working-class immigrant enclave, the Lower East Side is now known for its vibrant nightlife, indie music scene, and cutting-edge art galleries. It’s home to the famous Katz’s Delicatessen and the Tenement Museum.

1. Washington Heights, Manhattan, NY

• ZIP Code: 10031
• Population: 57,446
• Density: 36,581 people per square km

Topping our list is Washington Heights! While it doesn’t have the highest population, it packs a whopping 57,446 people into each square kilometer. Talk about cozy! This up-and-coming neighborhood is a goldmine for businesses looking to establish themselves in a growing market. From local bodegas to chic boutiques, there’s room for everyone – if you can find the space.

Washington Heights is known for its large Dominican population and rich cultural heritage. It’s home to The Cloisters museum and the historic Morris-Jumel Mansion. The hit musical “In the Heights” put this neighborhood on the map for many. Businesses that cater to the area’s Latino culture or tap into its growing appeal among young professionals priced out of lower Manhattan could find a receptive market here.

Tip: Comparison with National and State Averages

When analyzing a zip code’s population, it is essential to compare it with national and state averages to understand its relative density.

For example, the national average population density can be used as a benchmark to determine if a particular zip code is more densely populated than the national average.

State averages also offer valuable context. Some states, like California and New York, have higher population densities overall, which can make specific zip codes within these states seem less densely populated by comparison. However, when viewed in the context of their respective states, these zip codes might still be among the most populated.

Understanding these metrics and comparisons helps paint a clearer picture of why specific zip codes are more populated than others and how they fit into the broader demographic landscape of the United States.

Going Global: The World’s Most Crowded Postal Codes

Examples of the Most Populated Postal Codes Worldwide

After exploring the densest ZIP codes in the US, let’s zoom out and look at the global picture. We’ve analyzed GeoPostcodes population data to identify the most populated postal codes across the globe.

5. Dhaka, Bangladesh

• Postal Code: 1207
• Population: 571,028
• Density: 115,742 people per square km

Welcome to Dhaka, the capital of Bangladesh and home to one of the world’s most densely populated areas. With over half a million people packed into just under 5 square kilometers, this postal code is a bustling hive of activity.

Dhaka is known for its vibrant textiles industry and rapidly growing tech sector. For businesses, this means a massive potential workforce and a booming consumer market. If you’re in manufacturing, especially textiles, or looking to tap into a growing pool of tech talent, Dhaka should be on your radar.

4. Surat, India

• Pin Code: 395001
• Population: 910,211
• Density: 220,428 people per square km

Surat, often called the diamond city of India, is buzzing with life, housing over a million people in just this pin code. It’s a hotspot for the textile industry and a real melting pot of innovation.

Surat is where you want to be if you’re in the jewelry or fashion business. It’s got that entrepreneurial spirit and a growing market that’s hard to ignore. Think of it as a launchpad for connecting with customers and finding top talent.

3. Medellin, Colombia

• Código postal: 134001
• Population: 109,097
• Density: 149,166 people per square km

Medellin, once infamous for its cartels, has transformed into a hub of innovation and urban development. This densely populated area is part of Colombia’s second-largest city, known for its eternal spring-like weather.

Medellin has become a hotspot for tech startups and digital nomads. Its innovative public transportation system and focus on sustainable development have earned it accolades. For businesses in tech, urban planning, or sustainable solutions, Medellin offers a dynamic testbed and a concentrated market.

2. Tehran, Iran

• Postal Code: 58
• Population: 1,257,551
• Density: 284,936 people per square km

Tehran, the capital of Iran, boasts our second most populated postal code. With over 1.2 million people in this area alone, it’s a city of staggering density and rich history.

Despite geopolitical challenges, Tehran is a major economic center in Western Asia. It’s home to many of Iran’s industries, from automobiles to electronics. For businesses able to navigate the complex political landscape, Tehran offers a huge, concentrated market and a well-educated workforce.

1. Medellin, Colombia (Again!)

• Código postal: 134040
• Population: 192,202
• Density: 317,334 people per square km

Surprise! Medellin claims the top spot, too, with another postal code that outranks even Tehran in density. This showcases the extreme urbanization and population concentration in certain parts of the city.

This dual appearance of Medellin in our top 5 underscores the city’s remarkable density and the opportunities it presents. From urban planning challenges to infrastructure needs, Medellin is a city ripe for innovative solutions and business opportunities.

Scaling Across Borders? Here’s How Accurate Data Helps You Get It Right

Every region has its own challenges—finding your customers, picking the perfect location, or simply understanding how each market works.

Where Are the People? You’re expanding into new markets, but here’s the challenge—where should you actually focus? Targeting the wrong areas can waste time, money, and resources.

Are Your Sales Teams in the Right Places? Sales teams can’t cover everything, and sending them to low-potential areas is a waste. Overloading them with too many regions? Same problem.

Dealing with multiple data formats and languages? If you’re managing operations in multiple countries, reporting can quickly become a nightmare. Different zip code and address formats, metrics, different standards, no clear way to compare performance.

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With our global population by zip code database, you’ll have the data you need to make smarter, more confident decisions at every stage. From targeting the right audience, optimizing your sales territories, and choosing perfect store locations.

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Conclusion

Behind every ZIP code lies a story—a neighborhood full of people, potential customers, and untapped business opportunities. Whether you’re exploring the bustling streets of Brooklyn, the diverse communities of Queens, or even expanding beyond U.S. borders to places like Dhaka or Medellin, understanding population density is the key to making smarter decisions.

From inconsistent reporting systems to varying population metrics, the lack of unified data can make it difficult to compare performance, optimize strategies, or even find the right customer base. These challenges can stall growth, waste resources, and ultimately hinder global expansion.

But you don’t have to face challenges alone. We’ve got the data. You’ve got the ambition. Let’s make sure your global strategy is built on a solid foundation: Try GeoPostcodes data for free.

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