NameJohn Bowie Magruder 
Birth, Montgomery, Maryland
Death8 Sep 1812, Union Hall, Fluvanna, Virginia
Spouses
Marriage3 Feb 1791, , Prince Georges, , MD
Notes for John Bowie Magruder
M.C.Tutwiler ACGS application (#159) refers to Lib. G Fol. 124, Montgomery Co. MD Land Records for info. on him. I found nothing there, but a very useful document at folio 83: a Release of Dower by his mother Mary widow of James Magruder and his wife Sarah, relating to the property "Beall's and Magruder's Honesty", which he was selling in 1796 to Nathaniel Magruder (his uncle?) in preparation for moving his family and mother to "a distant part of Virginia."
"In 1800 or 1803 he settled with his family on the Rivanna River, in Fluvanna County, Virginia, his new home being called 'Union Hall' ..." [note inconststent dates] (ACGS YB1921, p. 49)
M.A. Tutwiler's ACGS Application (#560) refers to "wills in probate of Pr. Geo. & Montgomery Cos., Md."
Moved from Montgomery County, Maryland, to Virginia in 1792. Acquired extensive lands in Fluvanna County and built thereon a residence called Union Hall. Developed the waterpower of the Rivanna River and erected flouring and grist mills, cotton factory, saw mills, and machine shops for the manufacture of iron, leather, wooden goods, wagons, farming implements, etc. - the whole known as "Union Mills".
He was a man of unusual executive ability and his mills flourished for sixty years or more. By the terms of his will his slave were liberated and a hundred of them, who expressed the willingness to go, were given transportation to Liberia and sufficient funds to support them for a year.
Inherited "Honesty" in Maryland, which he sold to his uncle Ninian Beall in 1796 [ACGS YB1921, p.49].
Lummis records 6 more children, 5 with descendants.