Fastest Growing Counties in the U.S. in 2026: Top 10 Ranked

Among counties with at least 20,000 residents in both 2024 and 2025, Jasper County, South Carolina, ranks first in the Census Bureau’s latest ranking of the fastest growing counties by percentage, with its population rising 6.0% from July 1, 2024 to July 1, 2025. But the national county-growth picture becomes more useful when percentage change is viewed alongside population size.

Jasper added 2,195 residents during the year. Harris County, Texas, by contrast, gained 48,695 residents, yet does not appear in the Census Bureau’s percentage-growth top 10. One county led on speed; the other led on scale.

This 2026 analysis keeps those measurements separate. The primary ranking follows the Census Bureau’s percentage-growth table for counties with at least 20,000 residents in both 2024 and 2025, while a second comparison shows which counties added the largest number of residents.

Both comparisons use the U.S. Census Bureau’s Vintage 2025 Population Estimates and measure change from July 1, 2024 to July 1, 2025.

Fastest Growing Counties in the U.S. in 2026

The table below ranks the Census Bureau’s top 10 counties by percentage population growth from July 1, 2024 to July 1, 2025.

The Census ranking includes counties with populations of 20,000 or more in both years.

Population gain is calculated from the Census Bureau’s published July 1, 2024 and July 1, 2025 population estimates. Growth rates are the Census Bureau’s published one-decimal percentage changes.

Primary ranking metric: Percentage population growth.

Comparison period: July 1, 2024 to July 1, 2025.

Eligibility: Counties with at least 20,000 residents in both 2024 and 2025.

Source: U.S. Census Bureau Vintage 2025 Population Estimates.

The ranking should not be interpreted as a list of the counties that gained the most residents numerically. Percentage growth and numeric growth measure different aspects of population change.

Jasper County, South Carolina Ranks First

Jasper County recorded the fastest percentage growth in the Census Bureau’s published county ranking.

Its population increased from an estimated 36,338 residents in 2024 to 38,533 in 2025.

That represents an increase of 2,195 residents and a growth rate of approximately 6.0%.

The figures illustrate why percentage rankings need scale context. Jasper County led the Census Bureau’s published ranking of counties with at least 20,000 residents in both years, even though several much larger counties added many more residents.

Waller County and Kaufman County in Texas followed at 5.7%.

Kaufman County’s estimated population increased by 11,225 residents, substantially more than Waller County’s 3,761, but their percentage growth rates round to the same 5.7%.

Texas and Georgia Account for Most of the Top 10

Texas has four counties in the top 10 percentage-growth ranking:

• Waller County
• Kaufman County
• Liberty County
• Caldwell County

Georgia has three:

• Jackson County
• Long County
• Dawson County

Jasper County in South Carolina and Brunswick County in North Carolina also appear in the top 10, while Pinal County, Arizona is the only top-10 county outside the South.

The Census Bureau reported that nine of the 10 fastest-growing counties in this population-size group were in the South.

This geographic concentration identifies where rapid county population growth occurred during this particular one-year period. It does not establish that the same counties will continue growing at the same rates in future years.

Two Ways to Measure County Growth

County growth can be measured in at least two useful ways.

Percentage growth measures population change relative to the county’s starting population.

Numeric growth measures the number of residents added, regardless of the county’s starting size.

For the primary ranking in this article, percentage growth is the appropriate metric because it shows how quickly each county expanded relative to its existing population.

Numeric growth provides a different perspective by showing where the largest absolute population increases occurred.

These measures should remain separate because combining them into a single ranking would obscure the distinction between growth rate and growth scale.

Counties That Added the Most Residents

The Census Bureau separately publishes a top 10 ranking based on numeric population growth.

Harris County leads this comparison with an estimated gain of 48,695 residents.

Collin County added 42,966 residents, while Maricopa County added 35,411.

Pinal County is the only county appearing in both Census top-10 lists. It ranked seventh by percentage growth at 4.6% while also ranking tenth by numeric population gain, adding 23,654 residents.

That overlap is useful because it shows a county experiencing both relatively rapid proportional growth and a substantial absolute increase.

Why Small and Large Counties Produce Different Rankings

Suppose one county grows from 25,000 residents to 27,000.

It added 2,000 residents, but its growth rate is 8%.

Now consider a county growing from 1,000,000 residents to 1,030,000.

It added 30,000 residents, far more than the smaller county, but its growth rate is only 3%.

Neither measure is inherently better.

They answer different questions:

• Percentage growth shows how quickly a population is expanding relative to its existing size.
• Numeric growth shows where the largest number of additional residents is being accommodated.

That is why this article does not combine the two measures into a single composite ranking.

For the same distinction at a different geographic level, see our Fastest Growing Metro Areas in 2026 analysis.

What County Population Growth Can Tell You

County population estimates provide useful evidence about how the geographic distribution of U.S. residents is changing.

Rapid growth may be relevant to housing researchers because population change can affect the number of households seeking homes in an area.

But population growth alone does not tell us:

• Whether enough housing is being built.
• Whether home prices or rents are rising.
• Whether housing remains affordable.
• How many residents are homeowners or renters.
• Whether growth is concentrated in one city or spread throughout the county.
• Whether population change came primarily from migration or natural increase.
• Whether the local economy is growing at the same rate.
• Whether infrastructure and services are keeping pace.

A growing county can have abundant housing supply or a constrained market. Those conditions require separate housing data.

Population growth should therefore be treated as one indicator of local change rather than a complete housing-market measure.

Population Growth Is Not the Same as Migration

Population change and migration are related, but they are not interchangeable.

County population estimates reflect changes in the resident population from multiple components, including births, deaths, domestic migration, and international migration.

A county’s population can therefore grow even when one component is weak, provided other components more than offset it.

For that reason, this ranking should not be described as a list of the counties “where Americans are moving.”

A migration ranking would require a dedicated migration measure and a separate methodology.

The same distinction applies when comparing county growth with our Fastest Growing States in 2026 and Fastest Growing Cities in the US in 2026 research. Each geography has its own statistical universe and should be analyzed independently.

Does Rapid County Growth Mean Housing Demand Is Rising?

Population growth can contribute to housing demand, but the relationship is not one-to-one.

Housing conditions also depend on factors such as:

• Household formation
• New construction
• Housing-unit growth
• Vacancy rates
• Home prices
• Rents
• Mortgage rates
• Employment
• Household income
• Land availability
• Local development rules

A county could add population while also expanding its housing stock rapidly enough to accommodate additional households.

Another county could experience more pressure if housing supply expands slowly relative to household demand.

The county-growth ranking therefore provides demographic context, not a direct ranking of housing demand, housing shortages, or affordability.

Readers researching local markets can use our U.S. Cities & Metro Areas hub for additional place-based housing and population research.

Why a 2026 Ranking Uses 2025 Population Estimates

The year in the article title refers to when the ranking is current for readers, not to a population measurement extending through the end of 2026.

The Census Bureau released its Vintage 2025 county population estimates on March 26, 2026.

The annual comparison used here measures estimated resident population from July 1, 2024 to July 1, 2025.

As of the October 6, 2026 prepublication review, Vintage 2025 remains the Census Bureau’s most recent completed and consistent county population-estimate vintage.

Using the latest completed annual estimates keeps the county ranking based on one consistent Census vintage.

It would be misleading to describe these figures as population growth measured during calendar year 2026.

Why the Ranking Uses a 20,000-Person Threshold

The Census Bureau’s published percentage-growth table includes counties with populations of at least 20,000 in both 2024 and 2025.

This threshold matters because very small counties can record extremely high percentage changes after relatively modest numeric gains.

Using the Census Bureau’s published eligibility rule avoids introducing a separate arbitrary threshold for this article.

It also means the table should not be interpreted as ranking every U.S. county regardless of population size.

A different universe could produce a different top 10.

Methodology

This analysis uses the U.S. Census Bureau Vintage 2025 Population Estimates.

The primary table is the Census Bureau’s published Top 10 Counties by Percent Growth: July 1, 2024 to July 1, 2025.

The ranking universe consists of counties with populations of 20,000 or more in both 2024 and 2025.

Counties are ranked using their percentage change in estimated resident population.

For verification, the growth rates were independently recalculated using:

Population growth rate = ((2025 population – 2024 population) / 2024 population) × 100

The resulting percentages reproduce the Census Bureau’s published one-decimal growth rates after rounding.

The numeric-growth comparison uses the Census Bureau’s separate Top 10 Counties by Numeric Growth table.

Numeric gain was also checked by subtracting each county’s 2024 population estimate from its 2025 estimate. All 10 values reconcile with the published Census figures.

Why Census Vintages Should Not Be Mixed

The Census Bureau revises its post-census population-estimate time series when a new annual vintage is released.

That means the 2024 population estimate contained in Vintage 2025 may differ from the 2024 estimate published in an earlier vintage.

For a valid annual comparison, both the 2024 and 2025 values in this article come from the same Vintage 2025 series.

Earlier-vintage values should not be substituted into the ranking.

Frequently Asked Questions

What is the fastest growing county in the United States?

Jasper County, South Carolina had the highest percentage population growth in the Census Bureau’s published ranking of counties with at least 20,000 residents in both 2024 and 2025. Its population increased approximately 6.0%.

Which county added the most people?

Harris County, Texas had the largest numeric population increase in the Census Bureau’s separate ranking, adding an estimated 48,695 residents between July 1, 2024 and July 1, 2025.

Why is Harris County not ranked first among the fastest growing counties?

The primary ranking uses percentage growth rather than the number of residents added. Harris County started with a population of nearly five million, so adding 48,695 residents represents a much smaller proportional increase than the growth rates recorded by the percentage-growth leaders.

Why are only counties with at least 20,000 people included?

The Census Bureau applies that population threshold to its published top-10 county percentage-growth table. Using the same universe keeps this ranking aligned with the official source and reduces the effect of very small populations on percentage comparisons.

Is county population growth the same as migration?

No. Population change can reflect births, deaths, domestic migration, and international migration. A dedicated migration ranking would require separate data.

Does rapid population growth mean a county has a strong housing market?

Not necessarily. Population growth is one factor that can influence housing conditions, but prices, rents, construction, inventory, vacancies, incomes, employment, and financing conditions also matter.

Why does a 2026 article use population data through 2025?

Vintage 2025 is the latest completed county population-estimate vintage available for this analysis in 2026. It measures the annual change between July 1, 2024 and July 1, 2025 and was released in March 2026.

Can these rankings change when Census releases a new vintage?

Yes. Population estimates are revised as new annual vintages are produced. Future releases may revise prior-year estimates and produce a different ordering.

Conclusion

The latest Census estimates show that Jasper County, South Carolina led the official county percentage-growth ranking, expanding approximately 6.0% between July 1, 2024 and July 1, 2025.

Texas and Georgia account for seven of the top 10 counties, while Pinal County, Arizona is the only county appearing in both the percentage-growth and numeric-growth top 10.

The most important distinction is that rapid percentage growth and large numeric population gains are not the same thing.

Percentage growth shows how quickly a county is expanding relative to its existing population. Numeric growth shows where the greatest number of residents was added.

Both are useful, but they answer different questions and should remain separate when comparing population trends across U.S. counties.

Sources

• U.S. Census Bureau, Vintage 2025 County and Metro Population Estimates release, including the Top 10 Counties by Percent Growth and Top 10 Counties by Numeric Growth tables.
• U.S. Census Bureau, County Population Totals and Components of Change: 2020 to 2025, including Vintage 2025 county population and change files.
• U.S. Census Bureau, Vintage 2025 Population Estimates Methodology