The federal government is planning to sell the PortAmerica site in Prince George's County to one of the region's most prominent builders, boosting the hopes of county officials that the land beside the Potomac River might bloom into the small town of offices and homes foreseen a decade ago.

The prospective owner, H/P Companies L.C. of Fairfax, is working out details of the sale with federal officials. H/P was co-founded by John T. "Til" Hazel Jr., a pioneer in the region's development, and is now run by developers James W. Todd and Milton V. Peterson. The company built extensively in Northern Virginia, including the large communities known as Burke Centre and Fair Lakes.

The PortAmerica site, south of the Wilson Bridge, is considered by many to be the prime piece of undeveloped land in the county. As originally envisioned by planners and politicians, PortAmerica would have been the largest mixed-use development in the county and would have cost more than $1 billion to build.

PortAmerica was to be a small town almost unto itself, with nearly 2 million square feet of office space, 600,000 square feet of retail space, a hotel, restaurants, two marinas and nearly 1,400 "luxury" town houses and condominiums. H/P has not said how it wants to develop the 161-acre site -- the sale itself is still tentative -- but the company would have to seek an amendment from the County Council and the county Planning Board to change the development plan.

PortAmerica has a tortured history of setbacks, the most recent coming late last year when a cash-strapped developer's plans fell through.

But the handful of county officials who were aware of the impending deal said H/P Companies was perfect for the job of developing the property.

"This is a respectable company that has done work throughout the metropolitan region," said County Council member Isaac Gourdine, a Democrat whose district encompasses the PortAmerica site. "I think we're going to get something out of it."

Earlier this month, Todd, the company's president, wrote to Gourdine that the company had bought PortAmerica from the federal government and wanted to discuss development of the tract.

Todd's letter may have been a bit premature. The Resolution Trust Corp., which closed at the end of December after conducting an auction for the site, accepted the company's bid for the property. But the sale has not been closed, according to sources familiar with the auction.

The RTC, created to sell off assets held by failed thrift institutions, acquired the property about three years ago after it was appointed receiver for a failed California savings and loan. The Federal Deposit Insurance Corp. is handling the RTC's unfinished business.

County officials have been trying to get the property developed for nearly a decade. There was a ceremonial groundbreaking in 1987, but developer James T. Lewis wasn't able to get the project built, even though he and partners invested nearly $100 million in planning over 10 years.

Last year, the hopes of county officials were buoyed, then dashed, by New York investor Robert H. Sedrish, who announced in August plans to develop the site after submitting a bid in the RTC's first auction of the land. Sedrish acknowledged that he had not built anything on the scale of the PortAmerica project. But the issue became moot a month later when his $310,000 deposit check bounced and he filed for bankruptcy protection.

It could not be determined this week how much money H/P Companies offered for the tract. The RTC said last year it was seeking about $6 million for the site.

Stephen Katsanos, a former spokesman for the RTC, said agency policy prevented him from discussing a deal before it is closed, and he wouldn't confirm that H/P Companies was the accepted bidder.

Katsanos would say only that "the RTC accepted an offer, but it hasn't closed yet. It's the normal transactional real estate stuff. But I can't see it happening before around mid-February."

In a letter to Gourdine dated Jan. 5, Todd wrote: "H/P Companies is pleased to be the new owner of the PortAmerica property sold by the RTC. As we all know, PortAmerica can be a community of great significance for Prince George's County, the State of Maryland, and the Washington region."

In the letter, Todd said he hoped to visit with Gourdine soon and "hear your thoughts before we begin any serious planning." Todd said in the letter that he also had written to County Executive Wayne K. Curry (D).

Todd did not return two phone calls to his office yesterday.

According to a company brochure, it has developed more than 4 million square feet of office and retail space and 6,000 homes, mostly in Northern Virginia. Among its projects are Tyson-McLean Office Park, Fairfax Station and Reston Town Center. The company considers its premier development to be Fair Lakes in Fairfax, which has more than 7 million square feet of residential, retail and office space.

In 1989, Hazel's controversial plans to build a shopping mall next to Manassas National Battlefield Park died because of opposition from preservationists. The federal government authorized a $100 million buyout of the tract, giving the developer much-needed cash for other major projects.

"This is just extremely important for Prince George's County," said Dennis Murphy, chief executive of the Prince George's County Economic Development Corp. "To have a quality development project at such a gateway will set the tone of development that the county wants to attract. And it will set a very important tone for the region, not just Prince George's County."