America's missing middle: The shrinking 45-64 population

America has a missing-middle problem — and this one is demographic.

Why it matters: The shrinking 45-64 population could leave fewer experienced adults to run institutions, mentor younger workers and care for the fast-growing population behind them.

• This is the Gen X-ish squeeze: The age group includes most of Generation X, plus younger baby boomers.
• It also overlaps with the "sandwich generation" years, when many adults are juggling children, aging parents, careers and their own retirement worries.

By the numbers: The U.S. population ages 45-64 fell by 2.68 million from April 1, 2020, to July 1, 2025, according to new Census Bureau population estimates reviewed by Axios.

• The group declined 3.2% nationally, from 84 million to 81.3 million.
• The Northeast had the steepest percentage drop, falling 7.1%.
• The Midwest fell 6.2%.
• The West fell 2.7%.
• The South was the only region where the 45-64 population grew — barely — adding 18,749 people, or 0.1%.

State of play: The decline is happening as the country gets older overall.

• The U.S. median age rose to 39.4 in July 2025, up from 38.6 in April 2020.
• The 65-and-older population grew 16.2% nationally during the same period.
• The under-18 population fell 2.4%.

Zoom in: The demographic math is catching up.

• The 45-64 group isn't vanishing so much as aging up: Younger boomers are moving into retirement age, and older Gen X cohorts are filling in behind them.
• Coupled with aggressive internal migration, high costs of living and housing shortages in the Northeast and West are driving this experienced cohort southward.

Context: Gen X is smaller than the baby boom because it was born during the "baby bust" that followed the postwar birth surge.

• Birth rates fell sharply in the 1960s and 1970s as contraception became more widely available, women delayed marriage and childbirth and divorce and new family structures became more common.

Zoom out: The U.S. is not alone. Other wealthy countries also are wrestling with aging populations, slower workforce growth and rising pressure on public budgets.

• With fewer peak-earning workers to tax, nations face compounding pressure on how to fund services for massive, aging populations (like Social Security and Medicare in the U.S.).

Gen X generally refers to people born from 1965 to 1980 — those now ages 45 to 61.

• Baby boomers were born from 1946 to 1964. Millennials were born from 1981 to 1996.

The intrigue: Gen X was the last generation to experience peak school integration.

• Today's shrinking 45-64 group includes many adults who came of age in schools with broader exposure to students of other races than the students who came after them.
• As this group ages out of workplaces, school boards and local civic life, communities of color could lose leaders shaped by that rare integrated moment — just as schools are becoming more segregated again.

Between the lines: Corporations and local governments should be on high alert, analysts say.

• The 45-64 demographic typically represents peak earners who anchor municipal tax bases and possess decades of institutional knowledge.
• A declining middle-aged group could gradually thin the ranks of experienced workers, caregivers and civic leaders.

Yes, but: Overall, the U.S. population is still growing.

• The aggregate growth masks the severity of the dip in the mid-career population.
• An area might boast top-line population gains while quietly losing the veteran teachers, senior managers and local leaders who typically keep many communities running.