Understanding the U.S. Population’s Seismic Changes Since the Bicentennial
July 4th marks the 250th birthday for the United States, a significant milestone for any nation and a time to think about where it’s going … and where it’s been.
The USA is a very different place than it was during its last big birthday celebration, the 1976 bicentennial, and the data show how. The nation is more racially and ethnically diverse and better educated than it was 50 years ago. Its population is also much older.
But the American Communities Project brings a different way of measuring change. To get a sense of the shift over 50 years in our county types, we compared county population estimates from 1976 with county population estimates from the Census Bureau’s 2024 five-year American Community Survey.
It’s not a one-for-one match. The current ACP types were built in 2023 and based on the populations of the counties at that time. So many counties that are, say, Exurbs today were probably more like Rural Middle America in 1976.
Still, the growth patterns are interesting. The comparison between now and then shows a nation that has become more urban and also where population growth has stagnated or even reversed. It also provides a sense of the places and economic sectors that have developed most in the last 50 years.
The National Picture
Before turning to the ACP types, it’s worth taking a 30,000-foot view of the country. Even at that level, the changes over the past 50 years are striking.
Since 1976, the United States population has grown by more than 55% to more than 340 million people. The share of the nation that is white and non-Hispanic has decreased by almost 30 percentage points. The Black population has increased by about 3 percentage points. The Hispanic population has quintupled to about 20%.
At least that’s largely true. One needs to be careful when looking at old Census data. Back in 1976, the U.S. Census was ruled by the big decennial survey that shows up at your door every 10 years. Its non-decennial estimates were less formalized than they are today and less exact. But the racial and ethnic numbers are the best available for that time.
The other figures for college degrees and median age also show large changes. The percentage of Americans with a bachelor’s degree has more than doubled to roughly 36%. And the country has grown much older. In 1976, the median age in the United States was about 28, according to one estimate. Today, it is just under 39, according to the U.S. Census.
But the American Communities Project lens offers a different way of looking those changes.
Changes by Community Type
Five decades is a long time and the growth across the ACP types is far from uniform. Some have seen their populations skyrocket, others have been flatter, and one, the Aging Farmlands, has actually declined.
Even more surprising is the size of the drop in the population of the 268 Aging Farmlands — this county type fell by almost 25%. For those who follow the work of the ACP, that’s probably not a surprise. The story of big agriculture and farm industrialization has been a part of American farming since the 1980s farm crisis. Larger farms and fewer farms mean fewer people in the Aging Farmlands, but, again, the size of the drop is surprising and suggests a part of rural life has fundamentally changed.
The types that have grown fastest — the LDS Enclaves, Exurbs, and Hispanic Centers — all have different stories to tell.
For the LDS Enclaves, the growth (+153%) is partly about higher birth rates (along with people moving to those counties). For decades LDS families were more likely to have children and more likely to have more children than the average U.S. family. In 2015, the Pew Research Center reported that Mormon families averaged one additional child per family compared with the nation as whole. That may not sound like a lot, but, again 50 years is a long time, more than two generations, and eventually the numbers add up. However, data from recent years suggest that gap is narrowing as Mormon families have fewer children.
For the Exurbs, the growth (137%) is really part of the larger story of those communities. They tend to add people, especially young families, who are looking to get away from the city and move into a slightly bigger home. The Exurbs grow fast by their nature.
The Hispanic Centers’ growth (118%) mirrors the larger growth of the Hispanic population in the United States since 1976. When an ethnic group goes from 4% to 20% of the population, the communities that hold a lot of that population are going to grow.
Urban Centers
It helps to think of the Big Cities and Urban Suburbs as two community types that are part of the same story, the continuing urbanization of the United States. In terms of their broad demographic and socioeconomic makeup, the two types are becoming more similar. They are both racially and ethnically diverse and uneven — full of rich and poor as well as more college degrees and higher illiteracy rates.
In 1976, the Big Cities and Urban Suburbs held 45.6% of the nation’s population. In 2024, the number was 46.2%. That may not sound like a big jump, but the raw numbers show that each of the two community types has added more than 26 million people since 1976. That means even as the country grew dramatically in the last 50 years, Big Cities and Urban Suburbs have held on to their share of the population.
And they have done so as the country has adapted to the digital age, meaning they have been economically nimble. Those types are among the best educated and wealthiest in the United States today.
Add together the populations of the ACP’s more urban types — Big Cities, Urban Suburbs, Exurbs, and Middle Suburbs — and you have roughly 60% of U.S. population today. Back in 1976, they held about 57% of the population.
Seniors and Soldiers
Two other groups that stand out in the data are Graying America and Military Posts. The growth in those communities has far outpaced the national number by percentage, and the increases tell larger stories.
When the 2020 Census was released, one finding in the data was that a group of rural counties was growing faster than the nation as a whole. Most of those communities were part of Graying America, where the population has grown by 90% since 1976.
As Americans age, those with money are increasingly opting to move to rural, resort communities with urban amenities. A lot of those places are Graying America communities — everywhere from Lincoln County, Oregon; to Park County, Montana; to Door County, Wisconsin; to Lake County, Florida.
Over the last few decades, baby boomers with wealth have contributed to the growth of those places.
Military Posts have also experienced population growth that is higher than average, about 82% since 1976. There are probably a few factors driving that. Since 1976, Congress has worked through five rounds of Base Realignment and Closures, which meant some of the remaining bases got bigger.
Another contributing factor is probably the military-aligned businesses and contractors that have located near U.S. military bases in the last 50 years — some for expertise and some to simply serve the troops. Research and development have become a bigger part of the defense world, and there are fewer Military Posts to locate around. One result: Those remaining places have more people in them.
Taken together, the ACP population shifts tell the story of a nation that has broadly become more urban and more diverse than it was at the bicentennial. But that evolution has been uneven and there is a message in that finding.
As the nation marks its 250th birthday and celebrates its common history and common goals, the community-level differences outlined here remain a defining feature of the American experience. The political, cultural, and technological changes currently remaking the country are vast and likely to hit the communities in the ACP in different ways.
By “America 300,” the landscape of the community types may look dramatically changed.