Fielding Lewis, Sr. (1725-1781), was the son of John and Frances Fielding Lewis, of Warner Hall in Gloucester County. A prominent merchant and burgess, Lewis married GW's sister, Betty Washington (1733-1797), in 1750. Fielding was a second cousin to both GW and Betty. The Lewises, who had seven children that survived to adulthood, lived in Fredericksburg, Va., at a home built for Lewis in 1752, later called Kenmore. Lewis and GW were frequent business associates before Lewis's death near the end of the Revolution. At his death, Lewis left Betty in somewhat reduced circumstances. When GW assumed the presidency in 1789, he took steps to give two of Lewis's sons, Robert and Howell, a start in life. He made them clerks in his presidential household, Robert in 1789 and Howell in 1792. Upon Robert Lewis’s return to Virginia in 1791, he became Washington’s rental agent. Lewis's other son, Fielding Lewis, Jr., inherited from his father 1,000 acres in Frederick County, Va., though he spent much of his life in dire financial straits.

Lewis sometimes acted as an agent for GW, and handled some financial transactions for him. For instance, during the French and Indian War, Lewis was one of the persons who handled the shipping and sale of GW's tobacco. In 1772, Lewis also handled a cash payment that GW made to his mother, Mary Ball Washington (see Ledger B, 45, 62).

On 4 June 1761 GW paid Lewis “at the Fair Fredg” £40 for “two Lotts in Fredericksburg” (Ledger A, 8). The two lots GW bought from Lewis were supposed to be lots 107 and 108 on present Lewis Street between Charles and Prince Edward streets. GW must have been given instead, by mistake, titles to lots 111 and 113 on Charles Street between Fauquier and Hawke streets. The lots on Lewis Street were then, in October 1761, conveyed to Michael Robinson. In 1772 GW paid Robinson £275 in order to get titles to the two lots on Lewis Street. Finally in 1795 Fielding Lewis’s heir, John Lewis, sorted out the four lots and reconveyed them to the rightful purchasers.

In 1763 GW and several partners including Fielding Lewis and Burwell Bassett formed a company, “Adventurers for Draining the Dismal Swamp,” and the General Assembly of Virginia empowered them to construct canals and causeways through private land without being subject to suits for damages. The purpose of the undertaking was to harvest lumber while the swamp was draining and to farm the land once it became dry. GW documented a trip down the west side of the swamp, across the Perquimans River to a site near present-day Elizabeth City, N.C., then back along the eastern side of the swamp. Among the landowners in the region was Marmaduke Norfleet. In 1766, GW and Lewis bought from Norfleet 1,093½ acres in Perquimans County, N.C., and agreed to pay him £1,200 for the land (see Ledger A, 239; Ledger B, 18).

In 1777, Lewis bought for GW two lots in the town of Bath, also known as Warm Springs and later Berkeley Springs, for £100 Virginia currency. Washington visited Bath in September 1784 and engaged James Rumsey to build on the lots a dwelling house, kitchen, and stable.