This report is part of a series by the author on the results of the 2020 census.

In April 2021, the Census Bureau released the first set of results from the 2020 decennial census, providing a snapshot of the U.S. population for use in congressional reapportionment and redistricting. But recently, the agency released more detailed census information that shows a fuller picture of the population as it stood during the once-a-decade headcount.

These new statistics provide more information on the nation’s age structure and its race-ethnic composition, both nationally and across geographic areas. Among other items, they show that the nation continues to age, with the fastest population growth occurring among the older population while the youth population declines.

This aging is not “race neutral.” White Americans contributed substantially to older population gains compared to younger and middle-aged populations, which registered white declines.¹ Nonwhite residents accounted for all of the gains in post-baby-boomer populations. Although all race and ethnic groups are aging to some degree, the median age of white Americans is higher than all others in most geographic areas.

These patterns have led to a “racial generation gap,” in which the younger population—more influenced by immigration in recent decades—is far more diverse than older age groups. This demographic phenomenon has been shown to underlie many aspects of American social life, including its politics. While these national patterns are important in their own right, they vary considerably across states and regions, and thus exert more political and social influence in some areas of the country than others. Accordingly, this report pays special attention to the local dimensions of these demographic dynamics with interactive maps for states and metropolitan areas.

The US population continues to grow older, with some geographic variation

The new census data provides an authoritative picture of the nation’s continued aging. During the 2010-20 decade, the 65-and-older population (referred to here as the “senior” population) grew by nearly two-fifths (38.6%). This is over twice as much as during the 2000-10 decade and more than triple the rate of the 1990s (see Figure 1). It was the highest decade-long rate of senior growth that the nation has experienced since the 1880s, and the largest intercensal numeric gain (15.5 million) in its history. Underlying this gain was the aging of the large baby boomer generation, the first half of whom turned 65 during this decade.