Janet G. Whitehouse, a leader of Virginia conservation and historic preservation efforts, including a movement to block the development of a Disney theme park in Prince William County, died Dec. 24 at her home in Marshall, Va. She was 87.

The cause was complications from emphysema, said her son George Grayson.

Mrs. Whitehouse was active in many environmental and historic preservation groups. As co-chairman of the Goose Creek Association, a nonprofit conservation group in Northern Virginia, Mrs. Whitehouse and her husband, Charles S. Whitehouse, helped organize efforts against a proposed Disney theme park hear Haymarket, Va. After opposition from a coalition of public officials, landowners and concerned citizens, the plan was dropped in 1994. The site later became a residential development.

In 1995, Mrs. Whitehouse was a co-founder of the Mosby Heritage Area Association, a group that advocates for the preservation of the rural Virginia Piedmont area and conducts annual programs on local history for schoolchildren.

Mrs. Whitehouse also spent 16 years as a director of Stratford Hall Plantation, the birthplace and ancestral home of Confederate Gen. Robert E. Lee in Montross, Va. She served as vice president and a member of the historic home’s executive committee.

Janet Ketchum was a Pittsburgh native and graduated in 1943 from Chatham Hall, a private girls’ school in Chatham, Va.. She was a 1946 graduate of Vassar College in Poughkeepsie, N.Y.

She worked for two years as a political analyst for the State Department before her marriage in 1951 to William C. Grayson.

She began volunteering in the 1960s with the Audubon Naturalist Society, which her husband served as a volunteer president and board chairman. Mrs. Whitehouse later helped found a women’s environmental organization, Concern, and was active in many conservation projects concerning Virginia rivers, the C&O Canal and other efforts.

In 1970, Mrs. Whitehouse helped prepare the “Living Garden Calendar,” which offered advice on growing plants without the use of chemicals and was reprinted for many years.

She worked in the early 1980s as a projects director and development officer for the World Wildlife Fund. She was also a longtime member of the Fauquier and Loudoun Garden Club and chaired its conservation committee.

Other memberships included the Garden Club of America and Trinity Episcopal Church in Upperville, Va.

Her first husband died in 1980 after 29 years of marriage. Her second husband, Charles S. Whitehouse, a former U.S. ambassador to Laos and Thailand, died in 2001 after 16 years of marriage.

Survivors include three children from her first marriage, William C. Grayson Jr. and George Grayson, both of Upperville, and Katherine Grayson Wilkins of Washington; three stepchildren, U.S. Sen. Sheldon Whitehouse (D-R.I.) and Sarah W. Atkins, both of Newport, R.I., and Charles R. Whitehouse of Malibu, Calif.; and 10 grandchildren.

— Megan McDonough