There are many indications in the literature that the Smithfield and Walnut Grove Prestons were related in Ireland but I have as yet to find the actual connection. There were several inter marriages while in the state of Virginia.

According to Mary Preston Gray in her "Family Tree", Robert held a commission as surveyor from Oxford College, England, and shortly after his arrival in this country he began surveying. This apparently is not true but a certificate has been found dated 20 December 1779 from the College of William and Mary appointing Robert Preston surveyor. It was signed by James Madison, president of the college. After the organization of Washington County, he was appointed surveyor of said county by Thomas Jefferson, Governor of the Commonwealth of Virginia. At a council meeting on 9/2/1777 in Montgomery County, William Preston (Smithfields) produced a Masters from William & Mary College appointing him surveyor for Montgomery County. This was a very desirable position at that time. Wm. Preston of Smithfield and Robert Preston were engaged by Col. James Patton and the Loyal Land Company in surveying Patton's grants for 120,000 acres and later 800,000 acres in the Southwest Virginia, Kentucky area. Col. Arthur Campbell and family fought Robert's commission, but they were denied. After Robert produced a commission from Thomas Jefferson, Gov. of Virginia, dated 22 Dec 1779 the case was closed. Campbells and Prestons continued to have hard feelings and a duel was fought in which a Campbell was wounded. Under Documents refer to the Statement by Robert Preston at the time this position was being contested, 1799. (Link above for Statement of Service) He held this office from 1779 to 1831.

Robert also served in the Continental Army. He was excused from accompanying the troops to King's Mountain in September 1780, having married Margaret Rhea only two or three days before the troops marched. Robert was among the first Trustees for the town of Abingdon serving until 1803.

After Margaret's death in 1822, Robert Preston married Sally Dennison.

A cousin, Robert Coontz, Jr. has just discovered many letters written to and from Robert Preston which shed new light on "Irish Bob". A letter written by Robert Preston to Robert Preston dated 7/21/1793 from Philadelphia reads as follows: Cousin Samuel and I are safe arrived. Excellent Captain Hickey, but inhuman mate. Uncle John Davis and Aunt were well when we left Ireland but is [sic] dead. Your uncle is getting very frail. When we came to town, we met with Cousin Robert Divinport." Other correspondence refers to James Preston and his wife Sarah. And still others refer to Gilleland and Gilliland. Pretty sure Sarah was Sarah Gilliland. In another letter from James and Sarah Preston to Robert Preston dated 2 May 1805 from Donegall County reads as follows: "Dear Nephew" Part of my family is with you (Robert Preston, Jr.). "You and your wife's kindness...experienced your gratitude and affection long e'er you reached America...benefits which they have received." Mentions Alexander ? also...poor and afflicted condition of James Preston, Sr. of Derry. Ulcers on his hands and feet, confined to bed for a year. Remember us to Cousin Walter Preston and family; to son and daughter Dennison and family; to Robert and Daughter Preston. {James's} son Alexander. Cousin Sam Huston and family. Letters were hard to read and Robert Coontz and I are still trying to figure out who is who, however; it is clear that "Irish Bob" was Robert Preston and the son of James Preston, Jr. and Sarah Gilliland Preston and grandson of James Preston, Sr. When Robert Preston of Walnut Grove sent for him and he came to this country, Robert adopted him and called him Robert Preston, Jr.