A major Washington area builder announced plans yesterday for a commercial development in Prince George's County that promises to provide 30,000 jobs on 315 acres near Andrews Air Force Base and the Capital Beltway and is the latest in a series of projects officials hope will transform the county's image and economic profile.

The Presidential Corporate Center -- which joins the Konterra development in the north and PortAmerica on the Potomac -- will comprise 6 million square feet of office space, a hotel and convention center and four or five man-made ponds.

The development is expected to take 20 years to complete and to cost $750 million to $1 billion, said developer Lawrence I. Levin, who unveiled the project at the Mount Airy Plantation, a recently restored 18th-century manor house a few miles from the site where the center will be built.

Among the officials attending the press conference and luncheon were several County Council members, Rep. Steny Hoyer (D-Md.) and County Executive Parris Glendening.

"There is an economic boom in Prince George's County," Glendening said. "We're very pleased."

To support the development, Glendening said he included funds for improvements to Pennsylvania Avenue and a new Beltway interchange nearby in the $117 million revenue bond issue he proposed to the voters last week. The new center will be constructed along natural stream valleys that bisect property just north of where Suitland Parkway empties onto Pennsylvania Avenue (Rte. 4).

Levin, who built the Washington Science Center at Old Georgetown and Montrose roads near Rockville Pike in Montgomery County, said he plans to break ground in June on the first office building and a "visitor's center."

He said he selected the site because Prince George's County offers a better transportation network coupled with proximity to the nation's capital and more undeveloped land than other jurisdictions in the metropolitan area.

"All the activity was first in Montgomery County, Fairfax. Now it's spilling over into Loudoun, Prince William," he said. "Prince George's was more or less neglected, overlooked, on the wrong side of the tracks. But the last three or four years, it's come on line. That's where I'm putting my money."

The county, he said, is "wide open, with a network of preexisting roads unparalleled in any of the other counties. That's the name of the game, highway access. Montgomery's got one road, I-270, that's it. It's clogged and jammed. Loudoun and Prince William are too remote from the nation's capital."

So far, Levin said, he has spent $2 million of his own funds on planning and land acquisition for his Presidential Corporate Center -- so named because of its proximity to Andrews, home of the presidential aircraft. He said he intends to form a joint venture with an unnamed institutional lender to finance the project. He said he is not worried that he has no tenants lined up.

Although new office parks are springing up around the Beltway, a recent survey found a 17 percent vacancy rate in office buildings in the county. But H. Joseph Edwards, director of the Prince George's Economic Development Corp., said he has more recent figures showing an 11.6 percent vacancy rate, comparable to other metropolitan counties.

"We'll build on a speculative basis, as we always have developed," Levin said. "It's pioneering. When I started on Executive Boulevard in Rockville , it was all farm land. It started out as residential. I saw office buildings. People said, 'You're crazy,' but that's the way it developed.

"I think Prince George's is on the threshold of tremendous growth."

Some residents, who have vigorously opposed other developments, are pleased with the center.

Richard Moore, who farms 45 acres of tobacco directly north of the site, is among the supporters. "I'll tell you," he said, "from the Beltway to Upper Marlboro, everything is wide open. Starting out with something like this, it all might wind up the right way. Then, when I'm riding on my tractor, I can look up and say, 'Isn't that beautiful?' "