US counties aging fastest since 1990

Every US state and almost every US county has aged since 1990, as the baby-boom cohort moved through middle age and into retirement. But the speed differs sharply across counties. The 25 counties with the largest increases in median age since 1990 are below.

Sumter County, Florida leads at +28.5 yrs, moving from a median age of 40.0 in 1990 to 68.5 today.

#	Place	1990	Latest	Change
1	Sumter County, Florida	40.0 yrs	68.5 yrs	+28.5 yrs
2	Georgetown County, South Carolina	32.7 yrs	52.2 yrs	+19.5 yrs
3	Brunswick County, North Carolina	37.2 yrs	56.4 yrs	+19.2 yrs
4	Douglas County, Nevada	36.1 yrs	55.0 yrs	+18.9 yrs
5	Carroll County, New Hampshire	36.8 yrs	54.6 yrs	+17.8 yrs
6	Beaufort County, South Carolina	30.5 yrs	48.1 yrs	+17.6 yrs
7	Barnstable County, Massachusetts	39.5 yrs	55.4 yrs	+15.9 yrs
8	Nye County, Nevada	36.7 yrs	52.5 yrs	+15.8 yrs
9	Cumberland County, Tennessee	37.7 yrs	53.5 yrs	+15.8 yrs
10	Sussex County, Delaware	36.6 yrs	51.9 yrs	+15.3 yrs
11	Aroostook County, Maine	33.2 yrs	48.3 yrs	+15.1 yrs
12	Horry County, South Carolina	33.9 yrs	48.7 yrs	+14.8 yrs
13	Carteret County, North Carolina	36.0 yrs	50.5 yrs	+14.5 yrs
14	Santa Fe County, New Mexico	34.6 yrs	48.7 yrs	+14.1 yrs
15	Cape May County, New Jersey	37.7 yrs	51.8 yrs	+14.1 yrs
16	Clallam County, Washington	38.3 yrs	52.1 yrs	+13.8 yrs
17	Pike County, Pennsylvania	35.9 yrs	49.4 yrs	+13.5 yrs
18	Belknap County, New Hampshire	35.0 yrs	48.4 yrs	+13.4 yrs
19	Mohave County, Arizona	40.2 yrs	53.6 yrs	+13.4 yrs
20	Rutland County, Vermont	34.4 yrs	47.7 yrs	+13.3 yrs
21	Columbia County, New York	36.5 yrs	49.8 yrs	+13.3 yrs
22	Hancock County, Maine	35.8 yrs	49.0 yrs	+13.2 yrs
23	Franklin County, Virginia	35.2 yrs	48.4 yrs	+13.2 yrs
24	Somerset County, Maine	33.8 yrs	47.0 yrs	+13.2 yrs
25	Oxford County, Maine	35.0 yrs	48.2 yrs	+13.2 yrs

Key findings

• Sumter County, Florida leads the list at +28.5 yrs.
• The 25th-ranked county on this list — Oxford County, Maine — shows +13.2 yrs.
• Across the full universe of 1003 county rows with both data points, the typical change was +6.4 yrs.
• The top gainers concentrate in Maine (4 of the top 25), South Carolina (3 of the top 25), North Carolina (2 of the top 25).

Where the pattern sits geographically

Maine (4 of the top 25), South Carolina (3 of the top 25), North Carolina (2 of the top 25) together account for the bulk of the top of this list. Click any county above to open its CensusEasy page, which carries the full historical time series for every metric we publish (income, education, housing, commute, race composition, industry mix), plus its rank within its state and its national percentile on each metric.

How to read this

This ranking is sorted by absolute change, not by percentage change. Absolute change is the figure that lines up with how readers experience these numbers in everyday life ("the typical household here earns $X more than in 1990"). The percentage-change framing surfaces a different set of county rows — usually places that started from a low base — and we publish those rankings separately on the rankings pages.

A single metric never tells the whole story. The smallest gain on this list can reflect either change in the same population staying in place, or compositional change as some residents leave and others arrive. Companion studies on poverty, education, and housing cost together describe the fuller picture.

The pattern reflects two distinct dynamics: retirement destinations that have aged through in-migration of older households, and shrinking counties where younger residents have left and the people who stayed are older.