Smithfield Plantation is the historic home of the Preston family, one of the founding families of Blacksburg and Montgomery County, Virginia. It was built by William Preston (1729-83), who emigrated from northern Ireland with his family in 1737. He married Susanna Smith in 1761 and settled at Greenfield in Botetourt County in 1769. Preston established himself as a leader in the Virginia frontier by serving in the militia in the French and Indian and Revolutionary wars, in the House of Burgesses representing Augusta County from 1766 to 1768 and Botetourt County in 1769, and as County Lieutenant of Fincastle and Montgomery. He was appointed surveyor of Fincastle County in 1772 and moved his family to that area. He built Smithfield, named in honor of his wife, in 1773. Smithfield was the birthplace and home of three Virginia governors, including James Patton Preston (son of William), and John Buchanan Floyd and John Floyd, Jr. (grandsons of William).

In November 1958 the Association for the Preservation of Virginia Antiquities (APVA)authorized the organization of the Montgomery County branch for the specific purpose of acquiring and restoring Smithfield Plantation, the historic home near Blacksburg in Montgomery County, Virginia, built by William Preston in 1773. In 1959 Mrs. Janie Preston Brockenbrough Lamb, a descendant of Preston, donated Smithfield and 4.5 acres of land to the APVA. Restoration of the building was begun in 1962 when the APVA's Montgomery County Branch raised the funds for renovation and contracted with architects and contractors. The APVA is now known as Preservation Virginia.