Since 2000, the national median age – the point at which one-half the population is older and one-half younger – has increased by 3.4 years, with the largest single-year gain of 0.3 years coming in 2021, bringing it to 38.8 years, according to newly released 2021 Population Estimates from the U.S. Census Bureau.

The median age in over one-half (57%) of all U.S. counties and equivalents increased, and 74% of counties had higher median ages than the nation.

Metropolitan statistical areas consist of one or more whole counties or county equivalents and at least one urban area with a population of 50,000 or more. The median age increased in about 76% of metro areas (290) between 2020 and 2021.

Regionally, the Northeast was the oldest in 2021 with a median age of 40.4, followed by the Midwest (39.0), the South (38.6) and the West – which experienced the largest increase, 0.3 years to 37.7.

While aging, the nation is also becoming more diverse. Nationally, all race and Hispanic origin groups experienced population increases, apart from the White population, which declined slightly by 0.03%. The Native Hawaiian and Other Pacific Islander population was the fastest-growing race or Hispanic origin category between 2020 and 2021, increasing by 1.54% in the 12-month period. Hispanic (of any race) was the largest gaining and second-fastest-growing race or Hispanic origin category, increasing by 767,907 or 1.24%.

More detailed information is available in this announcement from the US Census Bureau.