Every ten years the Census Bureau counts everyone in the country. The 2020 Census tells us which cities are the biggest. To compare their populations you will use comparing large numbers.
Key idea
In the 2020 Census, the five largest U.S. cities were New York (about 8.8 million people), Los Angeles (about 3.9 million), Chicago (about 2.7 million), Houston (about 2.3 million) and Phoenix (about 1.6 million).
| Rank | City | State | People (2020 Census) |
|---|---|---|---|
| 1 | New York | New York | 8,804,190 |
| 2 | Los Angeles | California | 3,898,747 |
| 3 | Chicago | Illinois | 2,746,388 |
| 4 | Houston | Texas | 2,304,580 |
| 5 | Phoenix | Arizona | 1,608,139 |
| 6 | Philadelphia | Pennsylvania | 1,603,797 |
| 7 | San Antonio | Texas | 1,434,625 |
| 8 | San Diego | California | 1,386,932 |
| 9 | Dallas | Texas | 1,304,379 |
| 10 | San Jose | California | 1,013,240 |
Why it works
Why did these cities grow so big? Most grew where travel was easy: New York on a great harbor, Chicago where the Great Lakes meet railroads, Houston near the Gulf. Later, many people moved to the warm South and West, so Phoenix, San Antonio and Dallas grew fast in the last fifty years.
Worked example: Compare two cities
Which had more people in 2020: Phoenix (1,608,139) or Philadelphia (1,603,797)?
- Both have 7 digits, and both start with 1,60.
- Compare the thousands: 608 thousand is more than 603 thousand.
- So Phoenix had a little more.
Answer: Phoenix, by about 4,000 people.
Common mistake
People assume a state's biggest city is its capital. Of the ten largest cities in 2020, only Phoenix is a state capital. New York's capital is Albany, California's is Sacramento, Illinois's is Springfield, and Texas's is Austin (the 11th largest city).