Mildred Gregory (c1722-post1750) married in 1740, Col. John Thornton (c1710-78). He was appointed a justice of the peace in 1742, was sheriff in 1745, served in the House of Burgesses for Spotsylvania County, Va., 1753-55, and was a colonel in the Spotsylvania militia in 1756. They owned 3,600 acres of land and their official residence "Fox Spring" was on the 350-acre plantation along the Rappahannock River on the Caroline County side of Snow Creek. Their four daughters were Mildred (c1741-c62) who married c1757, a cousin, Col. Samuel Washington (1734-81); Mary (1743-92) who married in 1762, Brigadier General William Woodford (1734-80); Elizabeth (c1747-1811) who married c1770, John Taliaferro, Jr. (1746-1805), of Dissington, King George County; and Lucy Thornton (1750/1-70) who married in 1768, a cousin, John Lewis (1747-1825), son of Col. Fielding (1725-81) and Catherine Washington Lewis (1724/5-1749/50).

Mildred Gregory's mother was Mildred Washington (c1697-1747), only surviving daughter of Capt. Lawrence (c1659-98) and Mildred Warner Washington (1671-1701), who was born between October 1696 and March 1698, at Bridges Creek, Westmoreland County, Va. She inherited 2,500 acres which included the "Mount Vernon" site which she sold in 1726 to her brother, Augustine. She married (1) c1713/4, John Lewis (c1694-1718), of Gloucester County, Va., son of Edward and Susannah Lewis. She married (2) in 1718, Col. Roger Gregory (-c1730), of King and Queen County, Va. who was a plantation owner near the head of the York River. By the latter marriage she had three daughters, Frances (c1719-ante1794), Mildred (c1722-post1750), and Elizabeth Gregory (c1724-96), each of whom married three Thornton brothers, sons of Francis Thornton, Jr. (1683-1737), of "Fall Hill" near Fredericksburg, who was a burgess for Spotsylvania County in 1723, 1726, and a justice. Mildred Washington married (3) in 1733/4, Col. Henry Willis (1691/2-1740), of "Willis Hill," Spotsylvania County, son of Col. Francis Willis, of Gloucester County. He served in the House of Burgesses, 1718, 1720-26, 1728-34, and financially saved the fledgling town of Fredericksburg. Their son was Lt. Col. Lewis Willis (1734-1813).

See Albert Welles, The Pedigree and History of the Washington Family (New York, 1879), 116-117; W.G. Stanard, "The Thornton Family" (William and Mary College Quarterly, Richmond, Va., 1896-97), IV: 92-93, 161-162; John W. Wayland, The Washingtons and Their Homes (Genealogical Pub., 1944), 328, 337; Stella Pickett Hardy, Colonial Families of the Southern States of America (Genealogical Publishing Co., 1958), 519; John Augustine Washington (1920-2020), Descendants of Rev. Lawrence (c1602-52/3) and Amphyllis Twigden Washington (-1655) Five Generation Chart (Chevy Chase, Md. 1982); Dr. Justin M. Glenn, The Washingtons, A Family History, Volume One, Seven Generations of the Presidential Branch (Savas Beatie, El Dorado Hills, Ca. 2014), I: 36; James Houston Barr III, Lt. Colonel Nathaniel Pope, c1610-1660, of Virginia, Ancestor of Washington, Governors and Legislators, History of His Descendants (Louisville, Ky. 2018), 27-28.