America Hits a Record Median Age as Baby Boomers Keep Aging

The United States has never been older. The national median age reached 39.4 years as of July 2025, a record high, up from 38.6 five years earlier, according to the Census Bureau's Vintage 2025 population estimates. Fortune laid out what the numbers say about a country that is graying from the top down.

The single clearest driver is the baby boomers. The population aged 65 and older grew 16.2 percent between 2020 and 2025, faster than any other age group by a wide margin. Every younger cohort either crept up or shrank.

A country aging by cohort

The generational split in the data is stark. Adults 25 to 44, the core of the millennial generation, grew just 5.9 percent over the five years. The 18-to-24 group rose only 2.1 percent. Two groups actually got smaller: the under-18 population fell 2.4 percent, and the 45-to-64 range, roughly Generation X, dropped 3.2 percent. So the only age band expanding quickly is the oldest one, which is exactly what pushes a median age up.

Lauren Bowers, who leads the Census Bureau's population estimates program, tied the shift to a few forces at once. "The continued transition of baby boomers into retirement age, compounded by local migration and fertility patterns, is shifting the demographic makeup of the country," she said.

The boomer weight

The stakes go beyond a single statistic. The baby boom generation numbered about 79 million people at its peak, and as Fortune notes, that cohort holds roughly a third of the nation's housing stock and dominates its economic and political institutions. As boomers age in place, younger generations face a housing market and an opportunity structure shaped by a group that is now moving into retirement rather than out of it. The aging of the country is not just a demographic fact; it is a story about who holds assets and who is waiting for them to move.

The one region bucking the trend

The aging is not uniform. The South was the only region of the country that grew across every age group, expanding 6 percent overall against 3.1 percent nationally. The other regions shrank in multiple categories. The Northeast lost 7.1 percent of its children, the Midwest shed 6.2 percent of its midlife adults, and the West posted the steepest child decline at 5.7 percent. The country is getting older everywhere, but the South is the one place still adding people at both ends of the age range, largely in its outlying Sun Belt counties.

Where the age gap shows up

The national median hides enormous local variation, and that is where the data gets concrete. Retirement communities in the Sun Belt push some places past a median age of 70, while college towns and fast-growing family suburbs stay young, a split visible in the oldest cities and youngest cities rankings. At the state level, the contrast between the oldest states and the youngest is widening as boomers concentrate in some places and young families in others. For readers thinking about where an aging population is heading next, our look at what the U.S. population will be in 2050 traces the trend forward, and the best places to retire shows where the 65-and-older growth is landing.

You can check the median age and full age profile of any state, county, city, or metro on its page, or compare two places directly with the compare tool. The national snapshot lives at a glance.

Sources

Reporting: Fortune (June 26, 2026). Primary data: the U.S. Census Bureau's Vintage 2025 population estimates, released June 25, 2026, including "Census Bureau Releases New 2025 U.S. Population Estimates by Age and Sex" and "Populations in All Age Groups Growing in the South, Driven by Outlying Counties in Metro Areas". Program page: the Census Bureau Population Estimates Program.