The first Settlers of Augusta County, Virginia arrived in the 1720's primarily from Pennsylvania, Maryland and Eastern Virginia. The greatest number were Scot Irish Presbyterians from the province of Ulster in the north of Ireland, or the Pennsylvania and Maryland-born children of these immigrants. A significant portion of the early settlers were German-born immigrants, or their Pennsylvania-born children, of German-speaking immigrants from the Palatinate and other areas bordering the Rhine River. Most of the German immigrants were Lutheran, Reformed, or members of the Church of the Brethren. Many of the early Scots Irishm and German settlers came to Old Augusta from Old Chester County in southeastern Pennsylvania, following the "The Great Philadelphia Wagon Road" westward and then south to settle on Beverley Manor and Borden's Grant.
Many early settlers took up land on the 118,491-acre tract that the colonial government granted to William Beverley, Sir John Randolph, John Robinson and Richard Randolph, later referred to as "Beverley Manor". John Randolph, John Robinson and Richard Randolph relinquished their interests in the large tract to Beverley, as listed in one of the first patents, to John Moffett:
Map of Beverley Manor
In 1739, Benjamin Borden a New Jersey Quaker, received a grant beginning at the southern boundary of Beverley Manor. Borden was promised 1,000 acres for every settler he located, amounting in all to 92,100 acres. John McDowell, a surveyor, helped Borden locate his tract and was rewarded with a large acreage. The "Borden Tract" later became Rockbridge County, VA. In addition to the Scot's Irish, English and African-Americans were also among the early settlers in the area. Many settlers were of of English descent, coming into the area from eastern Virginia. African Americans were also among the early settlers, some free-born, but most enslaved. Although initially small in number, by the Civil War they represented 20% of the population. (Source: Augusta County Historical Society, http://www.augustacountyhs.org/history.html)
Augusta County was created from Orange County in 1738. For seven years, until the population grew large enough, Augusta’s records were kept in Orange. In 1745, Augusta elected a sheriff, a vestry, a county court, a minister, and a clerk of court. A courthouse was built on the same site in Staunton (originally called Beverley’s Mill Place) as the current courthouse. The county’s records have been kept continuously at the courthouse since 1745. In that year, the county included all of present southwestern Virginia, most of present West Virginia and even stretched to the Mississippi River. As people began to settle in those western areas, new counties were formed from parts of Augusta, beginning in 1769 with Botetourt County, then Rockingham and Rockbridge in 1778.
Sources: Augusta County Historical Society Website  ; "Ulster-Scots in Virginia, from Pennsylvania to Shenandoah", by Richard McMaster; "Kegley's Virginia Frontier: The Beginning of the Southwest", by E.F. Kegley; Wikipedia; Rootsweb.
Map of the Borden Tract