Is Your City Extreme?

Founded by the Spanish in 1565, St. Augustine, Fla., is the oldest city in the U.S. About two hundred miles to the southwest, Largo, Fla., is the city with the oldest population.

A city near Tampa, Largo saw the percentage of residents aged 85 and older nearly double from 3.4 percent in 1990 to 6.1 percent in 2009, according to U.S. Census Bureau estimates. The U.S. average is 1.8 percent for ages 85 and up.

Most cities in the U.S. are able to maintain a reasonable balance between rich and poor, old and young, healthy and unhealthy. Knowing the characteristics of a city help define its economic health and quality of life. It helps local government plan for what kind of services will be needed and what the tax base will be. Furthermore, it also determines what kind of businesses will flourish there and who will want to move there—or move away.

To find out which were America's Most Extreme Cities, compiled a list of extremes: hottest and coldest, fattest and fittest, oldest and youngest, richest and poorest, and reviewed data from a number of different sources, including the U.S. Census Bureau's American Community Surveys (ACS), the Bureau of Labor Statistics, the National Climactic Data Center, and others. The findings were adjusted to ensure that the town or city in question had minimum population requirements and were not skewed by the existence of such unusual institutions as prisons. (Click here to see more extreme places, based on ACS estimates.)

What's Hot, What's Not

How does a city go to extremes? In some cases, the answer is purely geographical. Lake Havasu City, Ariz., is the city with the hottest July temperatures. (Death Valley has higher temperatures, but it is not a city.) To use another example, Williams County, N.D., has the nation's strongest job market, thanks to an economy based on agriculture and oil.

In many other cases, though, the answer is more selective. "We're a country where segregation by economics, race, and ethnicity is part of the landscape," says William Frey, a demographer at the Brookings Institution. In some cases, demographic extremes can result from migration—or lack of migration, he adds, as people tend to want to live with people similar to them.

Supporting communities with huge demographic imbalances can be difficult. As regulators, businesses, and community leaders prepare to meet the demands of a U.S. population that is growing, aging, and struggling to find work, places with extreme demographic disparities will have to address their own outsize needs.

Small Towns, Big Families

One place that exceeds many demographic averages: the village of Kiryas Joel, a Satmar Hasidic community about 50 miles from Manhattan in New York's Orange County, where more than half the residents are younger than 15, a larger portion than any community nationwide with a population of 20,000 or more, according to Census Bureau estimates. (Hildale, Utah, has the highest proportion of children but has a population of only around 1,500.) By contrast, about one-fifth of the U.S. population is under age 15.

As birth control is not practiced and large families are customary, families in Kiryas Joel typically have eight to 10 children, and each year 150 new households are created, according to Ari Felberman, public relations director for the village. Only about one in three Kiryas Joel residents are aged 18 and older, and the village has a median age of 11.9, well below the national median of 36.8, estimates the U.S. Census Bureau.

This growth creates many challenges for elected officials, who are trying to meet ballooning housing, employment, and infrastructure needs. Also, with many single-income households, the village has a high poverty rate (though many trends often associated with poor areas, such as crime and divorce, are rare, due to strong family and community bonds, says Felberman). Median family income is less than one-third the national median, and more than two-thirds of residents live below the poverty level, according to 2005-09 five-year estimates from the Census Bureau's American Community Survey.

Few Jobs, Low Incomes

Poverty is even more pervasive in Escobares, a small border town in Texas, where an estimated one in nine residents lives below the poverty line. Many poor live along the border, but "we have some people who are making it," says Escobares Mayor Noel Escobar. He says he hopes to create more jobs and attract skilled labor to the area by working with nearby schools and colleges, but "this is a very long hill to climb."

Nationwide, the standard of living is generally high, but recent Census Bureau data show that 43.6 million Americans, or one in seven people, lived in poverty in 2009, the highest rate since 1994.

Poverty rates nationwide have only been exacerbated by the recent rise in joblessness. The U.S. unemployment rate, 9.4 percent in December, was higher than in many developed economies, according to the most recent international data from the U.S. Bureau of Labor Statistics. The unemployment rate in Canada was 6.6 percent, in Sweden 7.7 percent, and in Japan 4.6 percent, for example.

Extreme joblessness was most apparent in Imperial County, Calif., an agriculture and government-based labor market where an estimated 28.3 percent of the workforce was unemployed in December. The county also had the highest jobless numbers in the U.S. in 2008 and 2009, and in 2010 it had one of the highest foreclosure rates in California, 6.67 percent, according to RealtyTrac.

"It can be difficult for some places to break negative patterns," says Mark Mather, associate vice-president for domestic programs at the Population Reference Bureau, a nonprofit organization in Washington, D.C. Poor communities, for example, may have trouble retaining residents and attracting businesses due to joblessness and low income.

Blue Collar, White Collar

Even places that are disproportionately well off are not without challenges (of course, their problems are relatively easier ones to handle). In the Boston suburb of Newton, Mass., for example—the country's most educated city, where nearly half of adults have master's, professional, or doctoral degrees—administrators are struggling to protect the jobs of firemen, police, and teachers and keep the unemployment rate at about 6 percent.

It is always possible for a city to become less extreme. Not so long ago Detroit was one of the world's wealthiest cities and New York one of the most dangerous. Today, these realities have been turned upside down. Detroit's economy entered a downward spiral. Improvements to public safety in New York made it one of the country's safest big cities.

Extreme places have challenges that most places do not deal with. Still, if New York and Detroit are any example, the situation anywhere can change drastically. There will always be communities with demographic anomalies—even if they shift around. Who knows, maybe in 100 years, Largo may have the youngest population in the U.S.

Click here to see some of America's most extreme places.

Before it's here, it's on the Bloomberg Terminal.