The Washington PostDemocracy Dies in Darkness

The main reason states lost population in 2021? People moving to other states.

An empty street is seen in the Queens borough of New York City. (Jeenah Moon for The Washington Post)
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Between July 1, 2020 and July 1, 2021, the United States grew at a historically slow pace. The country added only about 393,000 new residents, most of them immigrants from other countries. But, of course, immigration was constrained because of the coronavirus pandemic — a pandemic that caused the number of deaths in the United States to surge. The country’s natural population increase (that is, the number of births minus the number of deaths) added only 148,000 people on net.

This isn't just an interesting bit of trivia. America is getting older, increasing the number of people who are retired as the number of people who are working and paying taxes grows relatively smaller. An America that's aging and not growing is an America that's facing a challenge.

But that bleak reality is not the point of this article. This article instead focuses on data released by the Census Bureau this week breaking down how population changed in each state over those 12 months. The story there is twofold. In half of states, more people died than were born. But the bigger driver of shifts in population was interstate migration.

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You can see the change in population on each metric on the map below. At left in each square, a black line marks the population on July 1, 2020. The increase due to births is followed by the decrease from deaths. Then the change from domestic migration, that dark purple arrow that goes up or down and, in most cases, determines whether the state’s population increased (gray squares) or fell (white ones).

Notice that the scale is state dependent. What we see is the relationship between the factors in each state. So in New York, for example, we see that the change in domestic migration — outward, on net — was much larger than the number of births and deaths seen in the state. In Utah, a very different picture: a lot more births than deaths (as is usual for Utah) with incoming domestic migration increasing the total.

In the 18 states that lost population over that period, 10 actually saw an increase in their natural population changes (that is, had more births than deaths). The decrease was instead a function of adults moving out.

We can look at that data differently. Here, we compare the natural population change from left to right and the change due to migration from top to bottom. States in the upper right quadrant saw gains both from migration and from births outpacing deaths. At lower right, states that saw more deaths and more out-migration.

You’ll notice that most of the states that lost population — in black — are below the middle line, indicating that they lost population from migration. (Also notice that these figures are normalized, shown as percentages of the total population in 2021.) A lot of the states that saw more births than deaths nonetheless also increased in population due to migration from other states. That includes Sun Belt states like Florida and Arizona.

Again, we should recognize those small, light-purple arrows on the map indicate the minor role played by international migration. In years past, Census Bureau data has made clear that immigration from outside the United States is a major driver of population growth in states. The advent of the pandemic meant a decrease in the number of people coming to the United States, meaning that states which often benefit from immigration did not see those gains.

The important question is whether that will rebound when (if?) the pandemic relaxes its grip. And if it population growth doesn’t recover, what that means for an aging country moving forward.