When Todd Morgan joined two partners who had started a business to support the Patuxent River Navy base in the 1980s, Lexington Park seemed like a Sleepy Hollow sort of town to him.

A decade later, the Defense Department began relocating thousands of people from Pennsylvania and Northern Virginia. In two years, the base's population increased from 12,300 to 17,600.

"It was like an invasion," said Morgan, who is president of a group that advocates for Pax River. "Everyone started coming down all at once."

From his office window, Morgan now sees signs for some of the biggest names in defense contracting. The company he helped start, Eagan, McAllister Associates, is spread across seven buildings in Lexington Park and employs more than 1,000 people.

St. Mary's County, where the base is located, has spent $350 million to renovate and expand its public schools and to widen to eight lanes the road that leads to the base, which employs 20,000 people.

Several regions in Maryland face similar though less intense challenges in coming years. Under the Pentagon's latest base realignment and closure (BRAC) recommendations, Maryland bases would gain more than 6,500 positions.

The increases planned for Fort George G. Meade, Aberdeen Proving Ground and the National Naval Medical Center in Bethesda would not be nearly as big as the transformation at the Patuxent River Naval Air Station in the 1990s, said military and local government officials.

But local leaders are confronting many of the same issues. Where newcomers from Florida and New Jersey choose to live and educate their children and how workers reassigned from Northern Virginia decide to commute are the pressure points.

"What happened at Pax River is a prime example of what communities ultimately have to deal with," said Tim Ford, executive director of the Association of Defense Communities, a Washington-based nonprofit organization that advises communities with active or closed military bases.

The Pentagon's list would add 5,361 positions at Fort Meade, 2,176 at Aberdeen and 1,889 in Bethesda. The BRAC plan must be approved by President Bush and Congress.

Retired Marine Corps Brig. Gen. J.M. "Mike" Hayes, director of Military and Federal Affairs for the Maryland Department of Business and Economic Development, and members of the state congressional delegation say Fort Meade is poised for growth.

"I don't think any of these challenges can't be dealt with," Rep. Benjamin L. Cardin (D-Md.) said at a meeting recently with local leaders. "This area has the space to grow."

Business and government officials have embraced the news as a potential boon for Anne Arundel, Howard and Prince George's counties. Fort Meade contributes $4 billion to the state's economy. It and its top-secret neighbor, the National Security Agency, together are among the largest employers in Maryland.

Even before the BRAC recommendations, discussions were underway at Fort Meade about moving two 18-hole golf courses to make way for office buildings. A Wal-Mart-style shopping plaza, hotel and convention center are envisioned for the post's capped landfill. There are plans to build or renovate 3,170 homes on the post by 2012, said Bill Mulvey of Picerne Military Housing.

Outside the gates, Fort Meade is a growing hub for defense contractors. Anne Arundel County Executive Janet S. Owens (D) said state and federal governments are working to widen Route 175. State money has been set aside to expand parking at the MARC train station a half-mile from the base, and Owens wants to add double-decker trains to ease congestion on Interstate 295.

"Traffic will be a concern," Owens said. "I don't want to see 295 turn into gridlock."

Under the Pentagon's recommendations, most of the services at the District's Walter Reed Army Medical Center would be moved to nearby Bethesda. Ellen Maurer, a deputy public affairs officer at the Navy medical center, said the 240-acre campus has the flexibility to grow, easy access to a Metro stop and several gates to accommodate new commuters.

"It's not like traffic would be forced through one tiny hole," she said.

The story of Pax River has the most in common with that of Aberdeen, Hayes said, because of the more rural character of the area. St. Mary's County leaders have encouraged Harford and Cecil counties to work together because of the effect of commuters and schoolchildren.

When the military announced its relocation plans for Pax River in 1993 and 1995, the school district braced for 1,000 new students. Instead, spouses and children arrived more gradually, adding 300 to 500 students a year, said J. Bradley Clements, chief administrative officer for the St. Mary's County public schools.

John Savich, the county's director of economic development, said the 40 percent increase in population also required "a psychological adjustment."

"A change like this affects everyone," he said.