Most regions across the country have seen the age of their population gradually climb as baby boomers begin to retire. But for some jurisdictions, the growth of this demographic group has been far more pronounced than others.

The Census Bureau released updated data this morning for all states and counties, showing pockets of the country are adding older residents fairly rapidly.

More than 43 million Americans now fall into the 65 and over age bracket, about a 7.1 percent increase from 2010. Over the same period, the nation’s total population also rose, but only by 1.7 percent.

A handful of states recorded steep increases up through last summer.

Nevada’s total population climbed 2.2 percent over the roughly two-year period ending in July 2012, while its 65 and older population jumped an estimated 11.3 percent. Colorado’s 65 and over population similarly rose 11.6 percent, compared to 3.1 percent for its total population.

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For a few of the jurisdictions experiencing the sharpest growth for this age cohort, the change hasn’t gone unnoticed.

One of the fastest growing such counties, Brunswick County, N.C., added more than an estimated 4,000 residents 65 and older since 2010. Huey Marshall, the county’s public information officer, said the region bordering South Carolina along the coast is experiencing an influx of wealthy retirees.

“You would not know there was a recession here. We’re issuing building permits as if nothing happened,” he said.

A few local churches expanded to accommodate larger congregations. Marshall said some theaters moved up their show times to earlier in the day, which he suspects may also be related.

Some of the highest concentrations of older residents can be found in the New England states.

While New Hampshire’s total population has fluctuated little, the state’s 65 and older population swelled 8.7 percent since 2010, according to Census Bureau estimates. Its median age also increased from 41.1 to 42 years – the largest increase of any state.

The state is not growing as fast as in years past, while migration has stalled, said Joanne Cassulo, a senior planner at the New Hampshire Office of Energy and Planning’s State Data Center.

According to the new estimates, the oldest states (in terms of median age) are: Maine (43.5 years), Vermont (42.3 years), New Hampshire (42 years) and West Virginia (41.7 years)

The following table shows changes in states’ 65+ population and total counts, comparing estimates for July 2012 with 2010 Census base figures:

As a whole, the nation’s median age stood at 37.4 years last July, up from 37.2 in 2010.

Only North Dakota, Hawaii, Alaska, Kansas, Oklahoma and the District of Columbia experienced a slight decline in their median age

The Census Bureau also released county-level demographic data, mostly mirroring that of states. Between 2010 and 2012, the median age rose in 2,557 counties, dropped in 510 and remained unchanged in 154.

The following map shows changes in counties' median age, comparing 2010 and July 2012 figures. Counties shown in dark green recorded the highest increases in their median age. (Click to open full-screen interactive map in new window)

New figures also provide detailed estimates for race, ethnic groups and gender. Other findings include:

  • Total deaths exceed births for non-Hispanic whites for the first time.
  • Asians were the fastest-growing race or ethnic group in terms of percentage change.
  • Since July 2011, six counties became majority-minority: Mecklenburg (N.C.), Cherokee (Okla.), Texas (Okla.), Bell (Texas), Hockley (Texas) and Terrell (Texas).
  • The Hispanic population increased by 1.1 million from July 2011 through 2012 to more than 53 million, mostly driven by births as opposed to migration.

Census county-level maps:

New 2012 Age Demographics

Baby Boomer Population Map

2010-2012 Population Growth Map