It won't be easy," said site sculptor Nancy Holt, looking around at the trash-strewn trapezoid of land she has been commissioned to turn into an "entry park" -- a patch of green, a work of art -- at the south end of Rosslyn.

The much-sought-after $36,000 commission, which includes both design of the park and a sculpture within it, was announced yesterday by Arlington County officials.

Funds will come from a National Endowment for the Arts "Art in Public Places" grant of $18,000 and matching funds contributed by the Cafritz Foundation, Marriott, McDonald's and several individuals, many of them real estate developers in Rosslyn. The entire project will cost an estimated $213,000.

The 170-by-100-foot park is located at the junction of Arlington Boulevard, North Lynn Street and Ft. Myer Drive, just a pop-bottle's throw from Arlington Towers and the Iwo Jima Memorial. More to the point, it is also directly across the street from a building now being completed by Theodore Gould and Holywell Corp. -- one of three buildings which are the subject of a suit now before the 4th Federal Circuit Court of Appeals.

The suit was brought by the Department of the Interior and the Justice Department against Arlington County and the developers, alleging that the height of the three buildings mars the Washington skyline.

The land for the park was offered by Gould in a trade-off with the county which permitted him greater "density" -- meaning size -- in the building he is constructing across the street.

"My works emerge from the places where I do them," said Holt, 41, widow of James Smithson.Smithson's "Spiral Jetty" in the Great Salt Lake is among the earliest and best-known "earthworks," or sculptures based on major changes in the landscape. Holt also works in this genre, and is best known for a large piece called "Sun Tunnels," sited in the desert outside Lucin, Utah. It consists of four giant, perforated concrete pipes, each 9 feet in diameter, aimed at the annual extreme positions of the rising and setting sun at the summer and winter solstices.

"No plans have been drawn yet," said Holt. "I want to spent some time here and research the history, the local architecture, the materials indigenous to this site. The site will generate the idea."

Will she use concrete? "Maybe," said Holt."There's certainly a lot of concrete around here." She expects to design the work this winter and complete it within a year.

Holt, who lives in New York City, will show a film about her work on Tuesday, Nov. 27, at 7 p.m. at the Arlington Arts Center, 3550 Wilson Boulevard, Arlington.