While New York and Los Angeles continue to hold on to their top spots for overall largest cities in the U.S., a much tighter race occurred for the No. 3 spot, which Chicago usually comfortably enjoys. Houston’s rapid population growth in the past decade nearly sent it over reigning No. 3 city Chicago, according to the latest U.S. Census Bureau figures.

Houston’s population grew 7.4 percent in the past decade, while Chicago’s population growth has dropped 7 percent. The Windy City, however, still was able to remain above Houston for population size, 2.7 million to 2.09 million respectively.

If Chicago doesn't change direction, it's obvious Houston could overtake Chicago and become bigger sometime in the next decade, says Steve Murdock, a previous director of the U.S Census Bureau.

So why is Houston experiencing such a rapid population growth? Experts attribute Houston’s growth to its low unemployment rate (8.1 percent compared to the 9 percent national average), the oil industry, low cost of living, and an influx of immigrants.

Plus, the main advantage is Houston is the least expensive major city to live in, says Stephen Klineberg, Rice University sociology professor.

Meanwhile, Chicago continues to lose residents. Some major factors: Eighteen percent of the city’s black residents left in the past decade, its rate of growth among the Hispanic population has slowed, and some residents have been forced to relocate due to the city’s demolition of housing projects.

We knew it would be very, very difficult to overtake Chicago in this census take,” says Jeff Moseley, president and CEO of the Greater Houston Partnership. “Those of us who follow the numbers know it's just a matter of time.

Source: “Census: Houston Sees a Population Surge, But Chicago Narrowly Remains Nation’s No. 3 City,” The Associated Press (Feb. 17, 2011)