They say three's a crowd...but what about 26,000? When it comes to population density (the number of people per square mile), some cities really push the envelope. And if you've ever walked the streets of these jam-packed locales, you've probably had first-hand experience with the squeeze of these tight spots.

Here, the 10 most crowded cities in the United States, based on land area measurements and population statistics from the United States Census Bureau.

1. New York City, New York. An international leader in business, fashion, and culture, it's not surprising that more than 8 million individuals choose to call the Big Apple home. So whether you're catching a Broadway show, checking out an art exhibition, or just trying to get to work, you're going to have to contend with an unbelievable amount of people: over 26,000 per square mile on this busy island.

2. San Francisco, California. When gold was discovered in California in 1848, San Francisco's population jumped to 10,000-and it's just kept on growing. Today the city is home to more than 700,000 residents, and a whopping 16,636 people occupy every square mile. Although the gold rush is long over, San Francisco still boasts many appealing attractions including the Golden Gate Bridge, Fisherman's Wharf, and the Exploratorium museum. Just be prepared for the long lines.

3. Chicago, Illinois. The name Chicago is thought to come from an Algonquian word meaning "onion" or "skunk." Although the natural inclination may be to run the other way if you see a skunk in your path, it appears that few people have fled from the Windy City. Its congested population hits 12,750 people per square mile. Perhaps classic Chicago attractions like Millennium Park, the Navy Pier, and the Sears Tower have kept the population up.

4. Boston, Massachusetts. If you've ever been in Boston's Faneuil Hall Marketplace, you have a pretty good idea of the extreme density of this city. Perhaps its many colleges keep the population levels high; it squishes 12,164 people into every square mile. Visitors to the city might make it feel even more crowded. Boston's unique cultural and historic heritage makes it a center of tourism, and its hotel industry ranks among the highest in the nation in occupancy.

5. Philadelphia, Pennsylvania. With attractions such as the Liberty Bell, the Franklin Institute Science Museum, and the Philadelphia Zoo, there's no shortage of spots to visit-and no shortage of crowds, either. With 11,233 people per square mile, this historical city and its suburbs could have residents bumping elbows with each other.

6. Miami, Florida. One of the world's year-round resort centers, millions flock to Miami each year for the beaches, restaurants, and bars. And while many eventually bid the sunny city farewell, more than 400,000 choose to call this Floridian city their year-round home. Pair that with the fact that Miami is about 35 square miles, and you've got a recipe for one very dense city: approximately 11,000 people per square mile.

7. Baltimore, Maryland. Baltimore is home to such impressive sites as the National Aquarium, Camden Yards, and the Babe Ruth Museum, but when it comes to breathing room, this harbor town strikes out. With more than 8,058 people per square mile, making your way through the crowds could prove to be a challenge.

8. Los Angeles, California. A popular vacation destination, L.A. attracts millions of tourists a year. Travelers come from far and wide to visit Universal Studios, stroll along Rodeo Drive, or catch a glance of their favorite actor. But it's going to be difficult to spot a movie star among the hordes of habitants: approximately 7,800 per square mile.

9. Minneapolis-St. Paul, Minnesota. Although they may not be as packed as some of the other locales on the list, the Minnesota twin cities are still pretty jammed with nearly 7,000 people per square mile. Fifteen Fortune 500 companies are headquartered in the Minneapolis-St. Paul metropolitan area, and their employees are likely to account for the swarming streets.

10. Detroit, Michigan. One of the largest manufacturing cities in the United States, the metropolitan area in and around Detroit is also one of the most packed. And although Detroit is the center of the automobile manufacturing industry, don't expect driving in this city to be easy-for every mile you go, you'll have more than 6,000 people to get around.