State population numbers reveal how many people live in each state, but one of the keys to understanding the complexities of the U.S. population distribution is to look at where people live.

At the county level, the geographic distribution of the estimated 325.2 million people in the United States clearly distinguishes two main areas where people live: “big” counties and “small” counties.

More than half of all residents live in just 143 big counties (in terms of the number of residents), according to an analysis of U.S. Census Bureau county estimates. That means less than half of the population is spread out across the remaining 2,999 small counties.

The range of population size of “small county America” and “big county America” is given in Table 1, and Table 2 shows how these counties are distributed across size categories.

Table 1: Range of population size among small and large counties

	Small Counties	Large Counties
Number of counties	2,999	143
Smallest population	88	485,846
Largest population	476,015	10,137,915
Median population	23,999	821,725

Table 2: Distribution of small and large counties by population in 2016

Size range	Small Counties	Large Counties
0-4999	308	0
5000-19,999	1006	0
20,000-99,999	1233	0
100,000-499,999	452	5
500,000-999,999	0	94
1,000,000+	0	44

The five smallest counties in the nation and the five largest are listed in Tables 3 and 4, respectively.

Table 3: Five smallest US Counties

County	State	Pop.
Kalawao	Hawaii	88
Loving	Texas	113
King	Texas	289
Kenedy	Texas	404
Arthur	Nebraska	469

Table 4: Five largest US Counties

County	State	Pop.
Los Angeles	California	10,137,915
Cook	Illinois	5,203,499
Harris	Texas	4,589,928
Maricopa	Arizona	4,242,997
San Diego	California	3,317,749

“Fourteen states don’t have any of the big counties,” said Larry Sink, Census demographer, who analyzed the data released June 22. They include: Alaska, Arkansas, Idaho, Iowa, Louisiana, Maine, Mississippi, Montana, New Hampshire, South Dakota, North Dakota, Vermont, West Virginia and Wyoming.

By contrast, there are 17 states where a majority of the population resides in big counties, as shown in Figure 1. In California, for example, more than 85 percent of residents (33.5 million) live in big counties. Ten million people live in Los Angeles, the nation’s most populous county.

“We see a predominance of these big counties on the east and west coasts,” Sink said. “Small counties are more commonly found in inland areas.” This is similar to demographic patterns commonly seen around the world. The map in Figure 2 shows how these counties are distributed across the country.

“The most populous counties are often transportation hubs and major ports,” Sink said. “The small counties are mostly found in landlocked areas in the Great Plains, mountains and deserts. It’s not uncommon for these counties to even be losing population over time.”

There is also a difference in racial and ethnic diversity. For example, 79 percent of Asians, 71 percent of Hispanics and 59 percent of blacks live in big counties. Small-county America is nearly three-quarters non-Hispanic white, whereas this group makes up less than half of big-county America.

The differences between the two geographies also extend to age. The median age in small-county America is 39.1 compared with 36.9 for big-county America, and 54 percent of people age 65 or older live in small-county America.

There is also a notable difference in the rate of growth. “Big-county America is growing nearly twice as fast as small-county America,” Sink said. “They’re not only getting bigger but increasingly more diverse.” Thus, if current trends continue, it’s likely that the divide between big and small will continue to become more pronounced in the future.

Haya El Nasser is editor of America Counts: Stories Behind the Numbers and Digital Content Strategist at the U.S. Census Bureau.