The Whitney Museum of American Art announced yesterday that its board of trustees has entered into a conditional designation letter with the New York City Economic Development Corporation to acquire two abandoned buildings at 820 Washington Street and 555 West Street at the southern gateway to the planned High Line elevated park that Dia Foundation recently decided against taking.

The decision by the Whitney to get the site means that it will abandon its plan to expand its existing building on the southeast corner of Madison Avenue and 75th Street.

The Whitney had only recently received approval for seven variances for that expansion that was to have been designed by the Renzo Piano Building Workshop with Cooper Robertson & Partners as associate architects. That expansion would have been just to the south of the museum?s existing building, a masterpiece of Brutalist architecture designed by Marcel Breuer, and behind the facades of several brownstone buildings it owns on the remainder of the avenue blockfront to 74th Street.

The Piano plan, which would have added about 65,000 square feet of gallery space to the museum?s existing 30,000 square feet, had run into opposition by some civic groups as had two other prior plans by famous architects, Michael Graves in 1985 and Rem Koolhaas in 2003.

The new space in the Meat Packing District would provide the museum with between 100,000 and 150,000 square feet of gallery space.

In a press release yesterday, the museum said it has ?invited architect Renzo Piano to design its expansion at the High Line, citing his ability to create dynamic museum architecture that privileges the works of art on view and that is responsive to its urban context.? Mr. Piano recently designed an expansion of the Morgan Library on Madison Avenue between 35th and 36th Streets.

Robert J. Hurst, the president of the museum?s board of trustees, said in a statement that ?We are proud to become the anchoring cultural organization for the High Line,? adding that ?The site will allow us to create significant architecture that is responsive to its urban context and make an important contribution to this evolving and dynamic part of our City.?

Leonard A. Lauder, the chairman of the board of trustees, said ?We have resources in hand to create the ideal Whitney for the 21st Century and beyond,? and Adam D. Weinberg, the Alice Pratt Brown Director of the museum said that ?our main goal is to be responsive to the art and ideas of the artistic community, our extraordinary collection, and to the evolving needs of our audiences.?

An article by Carol Vogel in today?s edition of The New York Times said Mr. Lauder said that in addition to expanding to the High Line site the museum would upgrade its Breuer building with new windows and a new climate control system.

The plan requires public review under the Uniform Land Use Review Process (ULURP).

A portion of the site will be used for offices and maintenance for the High Line and a meatpacking facility, the statement said.

Cultural Affairs Commissioner Kate D. Levin said in the release that the Whitney expansion to the High Line ?would help one of New York City?s premiere cultural institutions flourish, while enhancing public access to the High Line and addressing some of the long term needs of residents and businesses sin the area.?

The Whitney Museum was a pioneer in creating ?satellite museums,? one of which is on the first floor of the Altria Building on the southwest corner of 42nd Street and Park Avenue.

For many decades, the museum was housed in a very handsome building on Eighth Street just to the west of Fifth Avenue.

In recent years, the Meat Packing District and Chelsea have emerged as the city's hotbed of art galleries.