When the homeowners in the exclusive Hillandale subdivision in Georgetown bought their $350,000 town houses several years ago, they were assured by D.C. zoning officials that the replica of the Florentine-style mansion that sits on a hilltop overlooking their development would remain as a home for an individual family.

But now a local developer with a contract to buy the abandoned, 35-room manor wants to turn it into the centerpiece of a 28-unit condominium and town house complex, over the angry cries from nearby residents who charge they will be betrayed if the city approves the plan.

The residents point to a 1980 zoning ruling that said the mansion was to remain a single-family home.

In its heyday, the Hillandale mansion was one of Washington's most elegant gathering spots.

Home to the Archbold family, some of whom were heirs to the Standard Oil fortune, Hillandale had everything a millionaire could want: 16,000 square feet of space privately located on 42 hilltop acres peering down on the rest of Washington.

Today, the mansion, modeled after a 14th century Italian-style villa, sits empty, a dark and decaying shadow of better days.

In the rooms where the wealthy once played, only memories remain. Windows are boarded, paint is peeling and leaves blown through broken windows collect in the hallways of the now eerily quiet mansion that has been abandoned the past four years.

During that time, the Hillandale development was embroiled in a controversial bankruptcy case involving Texas developers and Arkansas banks that stalled its future.

Now the Wynmark Development Corp. wants to restore the 66-year-old estate, not as a single-family home for the extremely rich, but as part of a 28-unit housing complex for the moderately rich who can afford the $400,000 price tag for the six proposed condominiums in the mansion and 22 adjoining town houses. But residents contend that using the mansion as part of a condominium could set a dangerous precedent for homeowners who expect the city's zoning orders to provide planning for the shape of a neighborhood.

"We have relied on the {1980 zoning ruling} as the maximum amount of development that would take place at Hillandale. Now the developers just want to change the rules," said Susan Freed, a member of nearby Burleith Citizens Association, which also is fighting the rezoning.

The residents also charge that the 28 new units would add to the already congested area at 39th Street and Reservoir Road NW, across from Georgetown University Hospital.

The Hillandale residents who moved into the development before the original project went bankrupt said they prefer looking at the deteriorating mansion atop a hill in their back yards to having more development on the site.

"People feel they have a right to rely on the zoning commission's actions," said Richard W. Carr, one of the Hillandale residents leading the fight against the rezoning. Ironically, Carr is vice president of acquisitions for the firm run by his father, prominent Washington developer Oliver T. Carr. That company has faced its share of neighborhood opposition over past projects.

Carr said residents of Hillandale considered the 1980 zoning ruling when deciding whether to buy their homes. "I looked at the plan and concluded the development would have 267 units in it," he said. "Now all of a sudden we are being told that that's not quite true."

Along with citizen groups trying to stop the Wynmark plan, city officials also oppose rezoning.

Fred Greene, District planning director, said the neighborhood groups have valid concerns. "We also have some serious concerns about the modification." Greene's office is expected to report to the zoning commission next month.

In 1980, the D.C. Zoning Commission gave approval for the development of the 42-acre Hillandale tract, which called for the construction of 268 housing units, a mixture of town houses and detached homes. As part of the zoning panel's order, Hillandale's developer at the time, Hillandale Development Corp., agreed to keep the Archbold mansion as a single-family house or as a community facility for use by the development's homeowners. The zoning panel later revised the total number of new homes allowed to 267.

But four years later, after finishing only 54 town houses and one detached house, Hillandale went bankrupt -- the victim of the early 1980s interest rate crunch and a lagging market for upscale homes. The development firm was part of the once-healthy financial empire of Texan C.W. (Clint) Murchison, former coowner of the Dallas Cowboys.

In 1985, the Hillandale property was sold in a foreclosure action for $14.5 million to First Federal Savings Bank of Arkansas, the holder of the first mortgage on the estate. Earlier this year, construction began again on the remaining 212 homes permitted on the property under the 1980 order.

But now the bank, after several years of attempts to sell the mansion, is backing Wynmark's attempt to develop the site. Wynmark has a purchase contract with the lender for the mansion and the remaining 1.5 acres that are not part of the current development activities, if the rezoning is approved.

No date has been set for a hearing before the zoning commission.

Wynmark officials contended that the opposition is unjustified.

Kent Worthington, vice president of the firm, said the zoning commission and the original developer of Hillandale made "a mistake" when it said the mansion must remain as a single-family residence. "This is a very minor component of the initial {plan}," he said. "All we're trying to do is settle the last piece."

Angela Vallot, an attorney for the developers, said there is legal precedent for such a large-scale rezoning change. "Courts have held that homeowners do not have justifiable reliance on existing zoning when they buy their homes."

Vallot said she feels "the interest of the general community is to have something done with the mansion. It can't continue in its current state. It is falling apart."

Vallot said that with the nearby new homes on the once-secluded estate, the mansion's owners have had difficulty finding a buyer for the mansion, thereby making it impossible to adhere to the original order.

Wynmark's attempts to do something with the mansion have, so far, been fruitless. The firm first envisioned the site for nonprofit offices, a proposal that ran into vehement community opposition. Wynmark then suggested using the mansion for a health clinic or an inn, proposals also rejected by neighbors.