Washington had been expanding the estate by the purchase of surrounding parcels of land since the late 1750s and was still adding to the estate well into the 1780s, including the River Farm estate.
From 1759 until the Revolutionary War, Washington, who at the time aspired to become a prominent agriculturist, had five separate farms as part of his estate.
He took a scientific approach to farming and kept extensive and meticulous records of both labor and results.

In a letter dated 20 September 1765, Washington writes about receiving poor returns for his tobacco production:
Can it be otherwise than a little mortifying then to find, that we, who raise none but Sweetscented Tobacco, and endeavour I may venture to add, to be careful in the management of it, however we fail in the execution, and who by a close and fixed corrispondance with you, contribute so largely to the dispatch of your Ships in this Country shoud [sic] meet with such unprofitable returns?

In the same letter he asks about the prices of flax and hemp, with a view to their production:
In order thereto you woud do me a singular favour in advising of the general price one might expect for good Hemp in your Port watered and prepared according to Act of Parliament, with an estimate of the freight, and all other Incident charges pr.
Tonn that I may form some Idea of the profits resulting from the growth.
I should be very glad to know at the sametime how rough and undressd Flax has generally, and may probably sell; for this year I have made an Essay in both, and altho I suffer pretty considerably by the attempt, owing principally to the severity of the Drougth [sic], and my inexperience in the management I am not altogether discouraged from a further prosecution of the Scheme provided I find the Sales with you are not clogd with too much difficulty and expence.

The tobacco market had declined, and many planters in northern Virginia converted to mixed crops.
Like them, by 1766 Washington had ceased growing tobacco at Mount Vernon and had replaced the crop with wheat, corn, and other grains.
Besides hemp and flax, he experimented with 60 other crops including cotton and silk.
He also derived income from a gristmill which produced cornmeal and flour for export and also ground neighbors' grain for fees.
Washington similarly sold the services of the estate's looms and blacksmith.
He built and operated a small fishing fleet, permitting Mount Vernon to export fish.
Washington practiced the selective breeding of sheep in an effort to produce better quality wool.
Washington was not as invested in animal husbandry as he was in cropping experiments, which were elaborate and included complex field rotations, nitrogen fixing crops and a range of soil amendments.
The Washington household consumed a wider range of protein sources than was typical for the Chesapeake population of his day, which consumed a great deal of beef.

The new crops were less labor-intensive than tobacco; hence, the estate had a surplus of slaves.
But Washington refused to break up families for sale.
Washington began to hire skilled indentured servants from Europe to train the redundant slaves for service on and off the estate.

Following his service in the war, Washington returned to Mount Vernon and in 1785–1786 spent a great deal of effort improving the landscaping of the estate.
It is estimated that during his two terms as President of the United States (1789–1797), Washington spent a total of 434 days in residence at Mount Vernon.
After his presidency, Washington tended to repairs to the buildings, socializing, and further gardening.

In his will, written several months before his death in December 1799, Washington left directions for the emancipation of all the slaves who belonged to him.
Of the 317 slaves at Mount Vernon in 1799, a little less than half, 123 individuals, belonged to George Washington and were set free under the terms of his will.
When Martha Washington's first husband, Daniel Parke Custis, died without a will, she received a life interest in one-third of his estate, including the slaves
Washington had been expanding the estate by the purchase of surrounding parcels of land since the late 1750s and was still adding to the estate well into the 1780s, including the River Farm estate. From 1759 until the Revolutionary War, Washington, who at the time aspired to become a prominent agriculturist, had five separate farms as part of his estate. He took a scientific approach to farming and kept extensive and meticulous records of both labor and results.
In a letter dated 20 September 1765, Washington writes about receiving poor returns for his tobacco production:
Can it be otherwise than a little mortifying then to find, that we, who raise none but Sweetscented Tobacco, and endeavour I may venture to add, to be careful in the management of it, however we fail in the execution, and who by a close and fixed corrispondance with you, contribute so largely to the dispatch of your Ships in this Country shoud [sic] meet with such unprofitable returns?
In the same letter he asks about the prices of flax and hemp, with a view to their production:
In order thereto you woud do me a singular favour in advising of the general price one might expect for good Hemp in your Port watered and prepared according to Act of Parliament, with an estimate of the freight, and all other Incident charges pr. Tonn that I may form some Idea of the profits resulting from the growth. I should be very glad to know at the sametime how rough and undressd Flax has generally, and may probably sell; for this year I have made an Essay in both, and altho I suffer pretty considerably by the attempt, owing principally to the severity of the Drougth [sic], and my inexperience in the management I am not altogether discouraged from a further prosecution of the Scheme provided I find the Sales with you are not clogd with too much difficulty and expence.
The tobacco market had declined, and many planters in northern Virginia converted to mixed crops. Like them, by 1766 Washington had ceased growing tobacco at Mount Vernon and had replaced the crop with wheat, corn, and other grains. Besides hemp and flax, he experimented with 60 other crops including cotton and silk. He also derived income from a gristmill which produced cornmeal and flour for export and also ground neighbors' grain for fees. Washington similarly sold the services of the estate's looms and blacksmith. He built and operated a small fishing fleet, permitting Mount Vernon to export fish. Washington practiced the selective breeding of sheep in an effort to produce better quality wool. Washington was not as invested in animal husbandry as he was in cropping experiments, which were elaborate and included complex field rotations, nitrogen fixing crops and a range of soil amendments. The Washington household consumed a wider range of protein sources than was typical for the Chesapeake population of his day, which consumed a great deal of beef.
The new crops were less labor-intensive than tobacco; hence, the estate had a surplus of slaves. But Washington refused to break up families for sale. Washington began to hire skilled indentured servants from Europe to train the redundant slaves for service on and off the estate.
Following his service in the war, Washington returned to Mount Vernon and in 1785–1786 spent a great deal of effort improving the landscaping of the estate. It is estimated that during his two terms as President of the United States (1789–1797), Washington spent a total of 434 days in residence at Mount Vernon. After his presidency, Washington tended to repairs to the buildings, socializing, and further gardening.
In his will, written several months before his death in December 1799, Washington left directions for the emancipation of all the slaves who belonged to him. Of the 317 slaves at Mount Vernon in 1799, a little less than half, 123 individuals, belonged to George Washington and were set free under the terms of his will. When Martha Washington's first husband, Daniel Parke Custis, died without a will, she received a life interest in one-third of his estate, including the slaves
Mount Vernon