Anne Arundel County's population grew by 10 percent over the past decade, though some areas, including Odenton and Glen Burnie, exploded. Odenton grew by 81 percent, and Glen Burnie by 74 percent. The towns' growth rates were among the highest in the state.

Growth along the Baltimore-Washington Parkway and Interstate 95 is only expected to pick up in the next few years when as many as 15,000 workers arrive in the county because of a planned federal military base realignment.

Employment and shopping opportunities were also enhanced by the Arundel Mills mall in Hanover and the National Business Park in Jessup. Both projects are on track for expansion this year — with developers set to begin construction on a slots parlor and entertainment complex at the mall and a planned expansion of the business park.

"The western part of the county has been the real engine of growth," said Anne Arundel County Executive John R. Leopold, who used federal stimulus funds to create two new bus lines last year serving the MARC train station in Odenton and the Piney Orchard development as part of a strategy emphasizing transit-oriented growth. "It's location. People want to live close to where they work."

Harford County grew by about 12 percent in the last decade, the Census Bureau reported, with significant growth in Havre de Grace and Bel Air.

Jim Richardson, director of the Harford County Office of Economic Development, estimates that about 4,000 workers have transferred to the Aberdeen Proving Ground so far as part of the recent base realignment. That's helping support the area's housing market and giving a boost to retailers, he said.

It's also putting more cars on the road. "We are seeing more traffic," he said.

Brenda Desjardins, president of New Home Marketing Services, analyzes the local real estate market for developers and builders, and said new residents brought to the area by the base realignment are attracted to areas where there are already retail centers and other amenities.

"They get off on Route 24 and they see a Target, and they see a Barnes and Noble and they see things that they're comfortable with," Desjardins said. "That makes them feel a little more at home."

Baltimore Sun reporters Larry Carson, Nicole Fuller, Raven Hill, Jamie Smith Hopkins, Annie Linskey and Julie Scharper contributed to this article.