Virtually all of that growth occurred far to the east, beyond Interstate 35, the north-south freeway that bisects Dallas-Fort Worth, Austin, San Antonio and Laredo along the Rio Grande. Dallas-Fort Worth and Houston are the first and third-fastest growing metropolitan areas in the country, according to 2010 census data. They account for almost half of Texas' population and 56 percent of its growth in the past 10 years.
"Texas is in many ways two states," said Lloyd Potter, a demographer at the Texas Data Center. "When we look at the counties west of I-35, the bulk of them, probably 60 of them are losing population. It's becoming sparse in the west and that is going to become even more common."
The shrinking of Coleman County and the counties that sprawl west from the outskirts of Waco to the New Mexico state line is part of a larger phenomenon in the United States known as natural decrease. That is a demographer's phrase for describing places where more people are dying than being born.
Nearly a fourth of counties in the United States -- 760 of 3,142 -- are in a condition of natural decline, census data shows. These counties are spread across the Great Plains, the Dakotas, the Mississippi Delta, and reach into the coal fields of Appalachia -- into places where poverty, unemployment and an aging population have converged to steadily erase the number of rural Americans.
The great cattle ranches of Coleman County and its neighbors are withering away in size and number as west Texas ages and its children move away to better futures in Dallas and Houston.
"There ain't no cattle left," said Bob Eddington, who runs the Coleman Livestock Auction every Wednesday. "These people got old and there's nobody left behind them."
Between 2000 and 2009, 942 babies were born in Coleman County, and 1,392 people died.
Ken Johnson, a sociology professor and demographer at the University of New Hampshire, has been tracking the phenomenon and crunching the numbers since 2002, when he discovered 985 counties -- a record -- had achieved that dubious distinction. The Associated Press had reported earlier on Johnson's research.
In an interview with AOL News, Johnson said he found natural decline all across America's outback, in places like Ontonagon County on the shore of Lake Superior in northern Michigan, where there are two deaths for every birth. Ontonagon's long, slow fade began after the logging camps and mines closed down and the locals migrated south to the auto plants around Detroit. In the 2010 census, Ontonagon's population stood at just 6,780. In the past decade, 448 babies were born and 1,014 people died.
But natural decrease also occurs in rapidly growing counties in the Sun Belt, Johnson said, where large communities of retirees skew population statistics. In Charlotte County, Fla., on the Gulf Coast, deaths have outpaced births for 42 years. Between 2000 and 20009, almost twice as many people died (20,328) as were born (10,231). What's striking is that Charlotte County was growing at the same time. It gained 15,000 new residents overall because 25,000 new residents moved in.
"The first question is, can we stop this?" Johnson asked. "So little is known about it that people don't talk about it. Everybody thinks it's just a problem for them. There is no national recognition of this as a problem, nor at the state level is there much attention paid to it."
Yet the condition creates all kinds of troubles for communities, ranging from who will be left to care for its elders to how the diminishing tax base will support public schools.
"Imagine a county where there are virtually no young adults," Johnson said. "Who's going to be the volunteer fireman? Who is going to coach the athletic teams? Who are going to do all the social things that young adults tend to do to make communities a very different kind of place?"
Communities that lose their young eventually reach a tipping point where they cannot sustain themselves.
"Little communities care about their schools," Johnson said. "If the school has to be consolidated because there are not very many children anymore, that's a huge local issue. Towns come to blows over this kind of thing."
New census data released last Thursday, Johnson added, revealed that the pace of growth in urban areas is accelerating. Urban areas grew by 11.5 percent, compared to a 4.7 percent growth rate in rural America.
"Over time, urban America is going to get bigger at an even faster rate," Johnson said. "This has repercussions that reverberate all through the system, from employment to political power in Congress."
Natural decline can occasionally be reversed if immigrants move in, as has happened in Nebraska and Iowa, where Hispanic immigrants have taken jobs in meat packing plants. The infusion of immigrants has prevented natural decline from taking hold in the United States on a national scale as it has in Japan, Germany, Italy, Russia and Poland, where government leaders are grappling with the complexities of caring for aging populations.
In the United States, only West Virginia has experienced natural decline as a statewide condition, although Maine may soon join it, Johnson said. Even though West Virginia gained population in the last 10 years, deaths (193,308) still outnumbered births (192,926). The trend line in Maine, Johnson said, shows the gap between deaths and births narrowing there as well.
Natural decline first appeared toward the end of the Great Depression, Johnson said, but quickly disappeared after World War II and did not show up again until after the 1960s, when the baby boom ended.
By the early 1970s, as farming communities began to decline, more than 500 counties -- most of them in the Great Plains -- reported natural decrease. The phenomenon moved into the industrial Rust Belt, and coal country in Appalachia. It accelerated rapidly after 1990, reaching the peak of 985 counties in 2002.
Between 1990 and 2005, 514 counties with no history of natural decrease experienced it for the first time, Johnson said.
"Once it begins, it almost always continues," Johnson said. "It's sort of a downward spiral."
Coleman County has lived in a condition of natural decline for 42 years.
Named for one of the signers of the Texas Declaration of Independence (from Mexico), Coleman dates to 1858, when settlers arrived to run cattle and farm cotton and maize. The discovery of oil in 1917 improved the county's fortunes and by 1930, the county population had grown to 23,669 people. That turned out to be Coleman's peak.
By the 2010 census, Coleman County's population was down to 8,895, and the town of Coleman, the county seat, shriveled to just 4,709 residents.
Once Coleman had two drive-in theaters -- one for adults, one for kids. Both closed years ago. Only one clothing shop remains downtown, although Coleman still supports three funeral homes. Most residents shop in Abilene, 60 miles to the northwest, or drive 32 miles to the Walmart in Brownwood.
"Everybody blames the highway department when it came in and built a bypass that bypassed our downtown," said Joann Eddleman, who was born in Coleman, left for Houston and came home to retire in 2003. "But what really made us go downhill was farming and ranching petered out on us."
The number of beef herds in the United States is the smallest it has been since the 1950s, according to U.S. Department of Agriculture figures. The national trend is reflected in Texas, the nation's largest producer of beef. The Abilene Livestock Auction had three auctions a week in the 1980s. Now it's down to one, and the number of cows sold shrinks with each passing month.
"People just aren't running cows anymore," said Rex Bland, who runs the Cal-Tex Feed Yard on the outskirts of Abilene. "My mother was from Coleman County. My grandfather raised his family there and made a good living on three sections of land. Now if you own 10 sections of land and don't owe anyone any money, I'm not sure you can make a living on it."
Jack Horne's family has been in the ranching business since his great-grandparents arrived by wagon in 1877. Ranching was tough then. It's not become much easier in the 134 years since.
"You work seven days a week, 10 to 14 hours a day," Horne said. "Sometimes you can pay your bills. Sometimes you can't."
Horne's siblings left for the big city when Horne was growing up. His own two kids went away to college. But now his son, contradicting the demographic trend, came home to take over the ranch and guide it into a new generation.
Horne, 65, has watched the family-run ranches vanish, one by one. Some of the ranches are being bought up by professional people from Dallas and Houston, who turn the land into private hunting preserves for deer and quail.
"I know a couple of longtime families that are trying to keep it together," he said. "As you divide up one place, it gets so small, it can't support a family and then you have to sell."
The effect of Coleman's vanishing population is most visible in its schools. Coleman High School had 314 students when Richard Holloway became principal in 2006. Now it has 219. The loss created both difficulty and opportunity, depending on how you look at it.
"It's tough sometimes just managing your homework together with practice, but you do what you have to do," he said.
In a year, he too will be gone, off to college.
Eddleman, who is nearing her 70th birthday, writes for the Coleman News, heads the county Humane Society and is running for the city council. Her campaign centers around reviving Coleman's economy by turning it into a destination for retirees.
"That's how bad things are," she said. "We have to have old people run for city council."