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About 14.6 Million People Live in 40 Counties in Five States

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This story is part of an occasional series highlighting population and regional trends in the United States.

The Desert Southwest encompasses some of the country’s most arid territory and yet continues to be a fast-growing region of the United States.

In 2016, approximately 14.6 million people lived in the Desert Southwest’s 40 counties in five states.

For every decade between 1950 and 2010, the growth rate of the Desert Southwest was at least twice as great as that for the United States as a whole.

The Desert Southwest includes those counties with geographic centers that fall within the USDA Forest Service’s Tropical/Subtropical Desert Division. That division is characterized by annual precipitation of less than 8 inches per year.

Growth in the Desert Southwest

For every decade between 1950 and 2010, the growth rate of the Desert Southwest was at least twice as great as that for the United States as a whole. And in three of those periods, the growth rate in the region was at least triple the U.S. growth rate: 1950 to 1960, 1970 to 1980, and 1980 to 1990. In fact, in each of those decades, the growth rate of the Desert Southwest exceeded 40 percent.

While the region’s growth has decreased somewhat over the decades, it was still over 20 percent from 2000 to 2010. From 2010 to 2016 growth in the region continued to outpace that of the United States as a whole.       

States in the Desert Southwest

The Desert Southwest consists of parts of five states (Arizona, California, Nevada, New Mexico, and Texas). More than half of the populations of Arizona and Nevada in 2016 lived in the region.

Arizona’s share of its population living in the Desert Southwest was the highest: almost 9 out of every 10 residents in 2016, an increase from around 8 out of every 10 residents in 1950.  

Nevada had the second-highest concentration of its residents living in the region: almost three quarters of that state’s population in 2016, more than double the proportion in 1950.  By contrast, Reno, located in northern Nevada outside of the Desert Southwest, was a more populous city than Las Vegas in 1950.

The other three states into which the region extends (New Mexico, California, and Texas) ranged from about 20 percent (for New Mexico) to about 4 percent (for Texas) of their populations in the Desert Southwest in 2016.

Most Populous Counties in Region

Despite the region’s dynamic growth, four counties were among the five most populous in both 1950 and 2016: Maricopa County, Ariz. (Phoenix); Riverside County, Calif.; San Bernardino County, Calif.; and Pima County, Ariz. (Tucson).    

In 1950 the largest county, Maricopa County, had fewer than 350,000 people. By 2016, it remained the largest with a population of more than 4 million.  

Three other counties (Riverside County, Calif.; Clark County, Nev.; and San Bernardino County, Calif.) all exceeded a population of 2 million in 2016.

Industry and Occupation

Compared to the United States as whole, the Desert Southwest had a higher percentage of its employment in certain industries, according to the American Community Survey 2012-2016 five-year estimates.

They include:

  • Arts, entertainment, and recreation, and accommodation and food services.
  • Retail trade.
  • Transportation and warehousing, and utilities.

On the other hand, the Desert Southwest’s employment had a lower percentage than the United States as a whole in categories such as:

  • Educational services, and health care and social assistance.
  • Manufacturing.

In terms of occupational concentration, the region had a higher percentage of its employment in:

  • Service.
  • Sales and office.
  • Natural resources, construction, and maintenance.

But it had a lower percentage of employment than the United States in:

  • Management, business, science, and arts.
  • Production, transportation, and material moving.

Visit Our Infographic

Download List of All Desert Southwest Counties


Paul J. Mackun is a geographer in the U.S. Census Bureau’s Population Division.


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Page Last Revised - October 8, 2021
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