[7] Today the Fairfax County Park Authority operates the site with a specific focus on the Lee family.

[15] Richard severely curtailed tobacco production in favor of more sustainable crops, including wheat, corn, rye, and barley.

[18] After his election to the United States Congress in 1789, and for most of the next five years, Richard turned day-to-day management of his estate over to his brother Theodorick, who supervised spring planting and fall harvest.

[23] For several years after his purchase of Sully, Francis Lightfoot Lee II,[33] called F. L. by his family, was able to realize an annual profit of $1,500 to $2,500.

[34] At least part of that success was due to the "judicious system of husbandry" employed by F. L.'s wife Jane Fitzgerald Lee.

[36] Richard Henry Lee II's management was marked by negligence and apparent apathy towards the dishonesty of managers who were embezzling money from the estate: … mismanagement, having allowed an estate clear of debt, well stocked, well arranged under a good system as it had been for years' according to 'the universal belief and opinion of all friends, connections and neighbors' to be 'wasted and the debts lost.'

On June 23, 1830 the county court ordered his removal and, 'for the safekeeping and good management' of the estate ...[38]Control of Sully was next placed in the hands of Colonel George Washington Hunter in 1830.

[38] Gamble claims, "in no hands ... would Sully fare as well as when it had been assiduously maintained by a single, devoted, industrious proprietor.

With his brothers-in-law absent from the estate, Harrison took over representing their interests with the appointed administrator, Colonel Hunter, whom he replaced on July 18, 1836.

Those involved included previous owners of the property, Lee descendants, and a neighbor, Eddie Wagstaff, who later endowed the Sully Foundation that still provides support for the site.

[44] This campaign ended in 1959 when President Dwight D. Eisenhower signed legislation making Sully a national historic site.

[45] The Fairfax County Park Authority agreed to operate the site as a county historical park, and has since acquired an additional 60 acres (240,000 m2; 2,600,000 sq ft; 24 ha) to bring the total size of Sully Historic Site to approximately 120 acres (490,000 m2; 5,200,000 sq ft; 49 ha).

Interpretation at the site reflects the ownership of its founder Richard Bland Lee, which explains the park authority decision to have Sully "completely furnished with antiquities from the Federal period.