In 1965, DuVal ran for and was elected to the Virginia House of Delegates, in which he served for three consecutive terms.[124] He ran unsuccessfully for the United States Senate seat against Harry F. Byrd, Jr., in the democratic primary in 1970, but was subsequently elected to the Virginia State Senate in 1971 and 1975.[125] Because of his deep interest in conservation and environmental protection, DuVal received both the Virginia state award and the National Wildlife Federation award in 1970 for being the outstanding conservation legislator in the United States.[126] Consistent with this demonstrated interest, the DuVals decided to take a major step in conservation themselves. They entered into a perpetual easement agreement in 1971 with the Board of Supervisors, Fairfax County, Virginia, for the historic preservation of Salona, its surrounding outbuildings and eight acres of land. In the same legal instrument, a temporary easement for the remaining 44.3 acres was arranged for a period of at least ten years.[127] A later amendment, in 1974, provided for termination of the temporary easement only after January 1, 1990.[128] In 1975, a patriotic organization, the Society of the United States Daughters of 1812, obtained the DuVals' permission to place an historic plaque at Salona to commemorate James Madison's visit there in 1814. The bronze plaque was mounted in a foundation stone from what are thought to have been old slave quarters. They once stood in the side yard below the house. The plaque reads as follows: 1784-1815 SALONA "A place of great hospitality" Shelter for President Madison August, 1914 When British burned Washington Plaque placed by Virginia State Society National Society of United States Daughters of 1812 1975 Chapter V Notes Salona and the DuVals [119] Fairfax County, Virginia, Deed Book 635, p. 471; interviews with Susan and Clive DuVal by the author. [120] See Chapters II and IV; interviews with Clive and Susan DuVal by the author. [121] Nan Netherton, Donald Sweig, Janice Artemel, Patricia Hickin and Patrick Reed, _Fairfax County, Virginia: A History_ (Fairfax, Va.: Fairfax County Board of Supervisors, 1978), p. 546. [122] Netherton, et al., _Fairfax County_, p. 659; interview with Clive and Susan DuVal, January 11, 1979, by Nan Netherton; DuVal family scrapbooks, Volumes I-VII, 1944-1978, Salona. [123] McLean _Providence Journal_, April 29, 1960; _Washington Post_, April 23, 1961; Fairfax County _Sun-Echo_, January 15, 1965; _Washington Star_, March 18, 1965; Fairfax County _Free Press Newspapers_, September 29, 1966; _Globe_, May 14, 1970; Semi-Annual meeting program, November 14, 1976; DuVal family scrapbooks, 1961 and 1963, Salona. [124] Virginia General Assembly, _Register of the General Assembly from 1619-1976_ (Richmond, Va.: Virginia General Assembly, 1978).