In a far Northeast Washington neighborhood where most houses are vacant and drug gangs run the streets, a mother is trying to keep a tiny play area open for her 10-year-old daughter. But the threat she faces comes not from the local thugs but from the National Park Service, which says the play area sits on its land.

The dispute grew out of what appear to be honest mistakes on both sides over the ownership and boundaries of the lot in the 4100 block of Gault Place NE.

This week, the Park Service sent a crew and bulldozer to take down a fence and reclaim the land. But it backed off after Wanda Aikens pleaded with the Park Service not to begin work on the play area she'd made for her daughter, Olivia Cummings.

"If they do this, Olivia will have no place to play," Aikens said. "This is not a safe neighborhood, and I can't let her play in the streets."

The crew left, but Aikens is sure it will be back--and the Park Service has said its crew will return "soon."

Aikens, an art teacher, bought three lots in 1985 on Gault Place, a block from the Minnesota Avenue Metro station. The seller showed her the house and pointed to vacant lots on each side of the house as the property she was buying for $55,000. Her deed shows she owns three lots; however, the numbers of the lots are not in sequence.

Aikens said she "didn't think anything about that" irregularity. "You know how the District is. I just thought that was their way of numbering."

A first-time home buyer, she said she didn't realize she might need title insurance, so she didn't get any. She has not been able to locate the realty that sold her the home and lots, she said.

Several years ago, Aikens graded the land on one of the lots beside her home, filling in a deep gully. At the same time, she contacted the Park Service, knowing it owned nearby land. She thought the parkland adjoined the now-disputed lot. The Park Service came out and marked its boundary, putting two stakes in the ground at the edge of what would become Olivia's play area.

Park Service spokesman Earle Kittleman confirmed Aikens's account.

About five years ago, the Park Service decided to check its boundaries on a number of lots that it had purchased in the 1940s and 1950s in Northeast and Southeast Washington and that it planned to use for a road linking larger federal parks. The road was not built.

In the words of Park Service officials, they were looking for neighbors who had "encroached" on federal land. They determined Aikens was an encroacher two years ago when they realized they had set their Park Service markers in the wrong spots on Gault Place. Their land actually included the play area.

Kittleman said the lot "is clearly on federal parkland. We want to be good stewards of the land, and part of that is establishing our boundaries." The Park Service wrote to Aikens telling her to get off their land. She refused.

Aikens has a deed of trust note that lists three lots she owns, but until she checked city records this month to get a plat map for her block, she didn't know one of her lots was farther down the street. That lot has a house on it, and the house is marked for sale.

"Why would I want a house down the block?" she said. "I didn't buy that lot. I bought these lots." She has no interest in that house and no idea who put it up for sale. A real estate agent whose number was listed on a sign outside the house didn't return a call for this article.

According to the plat map, the disputed lot was given or sold to the Park Service in 1945. But that doesn't satisfy Aikens. She wonders why the Park Service did not realize that in 1987 when it set the markers for their boundaries.

Olivia's father, trucking company owner Randolph Cummings, said he spent about $11,000 filling the gully. He also lives in the neighborhood and said he wanted his daughter to have a safe place to play.

Yesterday, he came by to pick up Olivia for school, as he does every morning, and said he couldn't understand why the Park Service suddenly had to have the lot.

"It's like a life-and-death matter with them," he said. "They put the stakes in the ground. They let all these years pass, and now they have to have the lot yesterday."

Both sides said they had met several times, once with the local advisory neighborhood commissioner, but no resolution was reached.

For Cummings and Aiken, their greatest concern is the safety of their child. If they have to concede the land belongs to the Park Service, they'd like to have the use of it for another five years until Olivia no longer needs the play area.

Aikens said she doesn't earn enough money to hire a lawyer. "At $19,000 a year, I can't even afford to get my furnace fixed," she said. "We have been living without heat for two years."

The park superintendent for the area, John Hales, wrote to Del. Eleanor Holmes Norton (D-D.C.) yesterday in response to an inquiry that Aikens "consistently refuses to voluntarily remove her fence from Federal property. . . . We should also point out that the encroaching fence and swing set are scheduled to be removed by our Maintenance staff soon."

CAPTION: Olivia Cummings, 10, leans on a fence in front of the playground at her home on Gault Place NE. Wanda Aikens, Olivia's mother, is fighting the National Park Service's effort to level the playground, which she argues is on her property.