Robert Cobbs was often referred to as Robert, Junior, to distinguish him from his Uncle Robert Cobbs. He was the first son of Ambrose and Elizabeth. He is named in his father's Will in which he was bequeathed the home plantation, two slaves, and lots numbers 43-44 in Williamsburg. Robert sold these lots with the buildings on them on December 10, 1725, to John Blair, merchant. Robert's first three children were born in Williamsburg, before moving to Henrico County, about 1730. His son, Oather, was his first child born in Bristol Parish, Henrico County.

It will be recalled that in 1718, Joseph and Ann Frith were witnesses to the Will of Robert's father, in York County. In April 1740, he (Robert, Jr.) was named the Executor of the Last Will and Testament of Ann Frith, of Dale Parish in Henrico County. In this Will, he was specifically identified as the son-in-law of Ann Frith. It is noted from the Will that he also received the most substantial part of Ann's estate, despite the fact that a son John F. Frith was also named. John received 200 acres on the south side of the "second branch" including the plantation where lived, along with the family bible, A daughter Rebecca Ebbings received one shilling. Robert Cobbs received 200 acres on the north side of the "second branch" in addition to the plantation where he lived with all its adjoining lands, and "all the rest of my estate". Witnesses were George Hastenes, Danell Brown, and Mary Cobbs.

On July 25, 1749, Robert purchased 395 acres of land on the Staunton River, in Lunenburg County, Virginia, from a Robert Williams. This land was bequeathed to Robert's son, Samuel. In 1756, Robert bought 400 more acres in Lunenburg County, on the branches of Hunting Creek and Hunt's Branch. This 400 acres Robert sold to his son, Ambrose, in July 1761. By then, due to political reorganizations, this land was located in Halifax County, Virginia.

It is learned from Carrington's HISTORY OF HALIFAX COUNTY that a Robert Cobbs, Gentleman, was appointed Captain of a Company of Foot Soldiers in 1754, by the Honourable Governor, in the southern district of Lunenburg County (This was the district that became part of Halifax County, in 1752).