One is in California, best known as the country's most ozone-polluted city. The other is a Denver suburb. So what do Bakersfield, Calif., and Aurora, Colo., have in common?

They're both now bigger than Pittsburgh, according to U.S. Census Bureau figures released early today.

Pittsburgh fell to 59th in population among U.S. cities, a drop of two spots since the 2006 figures. Its July 1, 2007 population was 311,218.

The census figures represent only populations within city limits, not greater metropolitan areas.

It wasn't that Pittsburgh's population change was so drastic -- it lost 2,450 residents -- or that being ranked 59th among the country's 262 incorporated places with populations of more than 100,000 is so awful. If this were high school, Pittsburgh would rank in the top quarter of its class, possibly good enough to get into a fine college depending on SATs and extracurricular activities.

But some joie de vivre erodes when a city boasting the amenities that Pittsburgh does has fewer people than say, Mesa, Ariz., (452,933) or Arlington, Texas, (371,038) or even Wichita, Kan. (361,420). How many people realize that Columbus, Ohio, has a population of 747,755, nearly 2¹/₂ times the size of Pittsburgh?

Still, there are things to be grateful for, the biggest of which is that census figures show Pittsburgh is ranked one spot ahead of Toledo, Ohio.

Also, the city was not one of the biggest losers of population during the year. Other cities, including some of Pittsburghers' least favorites, lost more. Cleveland was hit worst, losing 5,067 residents. Other losers, were, in order, Columbus, Ga., Baton Rouge, La., Philadelphia and Baltimore.

The big winners, population-wise, between 2006 and 2007? New Orleans, whose population rose nearly 14 percent, and Houston, which gained 38,932 residents.

Taking a longer view of the new census numbers, between 2000 and 2007, six cities passed Pittsburgh in population: Aurora, Bakersfield, Cincinnati, Anaheim, Tampa and Santa Ana, Calif. During that same period Pittsburgh lost 22,609 residents.

The fastest growing cities during that seven-year period were McKinney, Texas, whose population more than doubled to 115,620, and North Las Vegas, whose population rose about 84 percent to 212,114.