A D.C. Superior Court judge, weary of listening to squabbling heirs who couldn't decide how to sell the magnificent Tregaron estate in Northwest Washington, yesterday ordered it sold for $4.6 million to the Washington International School and a developer who plans to build luxury homes there.

The sale, approved by Judge Milton D. Korman over the vociferous objections of a lawyer for three of the six heirs, will allow the school to continue to use the elegant Georgian mansion on the property it now leases from the heirs, where Tregaron Development Corp. builds homes worth $200,000 or more on the heavily wooded, rough terrain surrounding the school.

Korman's orders wrote an end to a significant chapter in the decade-long fight among descendants of Washington Lawyer Joseph E. Davies, a controversial ambassador to Moscow before World War II, self-made millionaire, husband of cereal heiress Marjorie Merriweather Post and grandfather of former Maryland Sen. Joseph D. Tydings, an heir who supported yesterday's sale.

But the judge's sale of the 20.7-acre site at 3100 Macomb St. NW, just west of Connecticut Avenue, seemed certain to spark new controversy over one of the last major pieces of undeveloped Washington land.

The three heirs who objected to the sale -- Emlen Davies Evers of Cleveland, one of two Davies daughter still living, and two of his granddaughters, Jennifer Fitch Moleon and Suzanne Walker Wright of Washington -- immediately said they would appeal Korman's order. They claimed that the property is worth as much as $6 million, was not marketed properly and that their bid to buy out the share owned by Tydings, his mother and sister was better than the one Korman accepted.

Affluent, well-organized citizen groups in the Cleveland Park and Woodley Park neighborhoods adjoining Tregaron have long viewed the estate as their own private sanctuary from the noise and congestion of the Connecticut Avenue corridor.

As a result, many of Tregaron's neighbors have steadfastly opposed development of the tract. Some of them have recently recognized that under the land's current zoning, a developer could level the hills and cut down the trees and put up homes like their own $200,000 houses on one-sixth acre lots -- much to their dismay.

Arthur V. Meigs, president of the Cleveland Park Citizens Association, said the neighbors' prime goal now "has to be to preserve the character of the neighborhood," which he described as "quite and residential."

E. Davis Harrison, a lawyer for the developer, said Tregaron Development officials have already hired two architects, Robert Ziegelman of suburban Detroit and Chloethiel Woodard Smith of Washington, to draw plans for the project.

Harrison said that while the exact shape of the planned development has not been decided, about 125 to 175 homes might be built, quite possibly in clusters so that as much of the pristine landscape could be preserved.

He said that under one possible configuration, six acres around the school would be preserved and about half of the remaining 15 acres developed.

Harrison said that after the school and Tregaron Development go to final settlement on the property in the next 120 days, they would meet with neighbors and city officials to try to arrive at an acceptable plan.

"We're not interested in a fight," Harrison said.

The Development firm is headed by Alan R. Novak, a Washington real estate developer and investor who said he has previously invested in various D. C. condominium and apartment projects. One of the investors in the firm is Louis Marx, heir to a toy manufacturing fortune.

Washington International School, which previously sought to buy Tregaron on its own, has occupied the stone-columned mansion on the estate since 1972. The school, which also owns another facility in Northwest Washington, has 335 pupils in grades four to 12 at Tregaron, about 50 percent of them foreign students and 16 percent inner-city youths on full scholarships.

The school, established on the Wilsonian premise that international barriers should be torn down requires that students become proficient in either French of Spanish. Its classes are taught in those languages one day and English the next. Tuition ranges from $1,500 a year for the Half-day nursery classed at its building on Olive Street NW, to $3,500 for 12th grade students.

Over the years, the heirs of Davies, who died in 1958, have had several offers to buy the property. But they could never agree among themselves how much the property was worth.

Three recent appraisals placed the value of Tregaron at $3.5 million, $3.8 million and $3.95 million.

But the Evers-Moleon-Wright faction thinks the property is worth substantially more than the $4.6 million Korman sold the property for yesterday. They also contend that the $4.5 million they offered for the property was actually a better bid than the $4.6 million after because it will be reduced by $200,000 in brokers' fees.

But Evers, Moleon and Wright did not renew their bid in court yesterday while Korman waited about three minutes for anyone to stand up and make an offer.

"We never got a fair shot," Wright said bitterly after the hearing.

"It's the biggest travesty of justice I've ever seen," echoed her aunt, Emlen Evers.

The two women and their lawyer, Nicholas A. Addams, contend that James A. Crooks, a lawyer Korman appointed to entertain bids from prospective buyers, failed to search hard enough for purchasers.

Addams, in a string of acerbic exchanges with Korman, asked that the sale be put off for six months and that Crooks be fired, a request Korman had previously rejected.

"What you're saying has been ruled on already," the judge angrily told Addams. "You took it to the [D.C.] Couth of Appeals and they threw [an immediate appeal] out.

"If you have anything new, state it," Korman said, pounding the bench with his fist.

Addams, and his clients agreed to let the school stay at Tregaron for another academic year if they could win a delay in the sale of property. But Lawyer Harrison said Tregaron Development's offer to buy the property would be withdrawn if the sale were delayed.

Moments later, Korman then searched the courtroom and said, "I offer the property once . . . twice . . . third and last call" for other offers.

"Hearing none," the judge said. "the property is sold."