If you are tracing a hard-to-find Scottish ancestor, into or through Virginia, consider Prince William County Records. Most of the property records have been transcribed, indexed, and published. And the original county records are available on microfilm from the Family History Library and can be loaned to local centers for study. The records are amazingly complete.
Dumfries VA was an early Scottish trading center, although much of the land today is included within Quantico Marine Base. See Robert D. Mitchell’s Commercialism and Frontier: Perspectives on the Early Shenandoah Valley. (Charlottesville VA: University of Virginia Press, 1977.) Mitchell describes the Scottish factory system whereby raw materials were gathered and shipped from the Shenandoah Valley through Dumfries as a port city to Glasgow Scotland. Here they were manfactured into goods which were sold through the same factory system to the inhabitants. Maps show where each warehouse and store was located between Dumfries and Staunton.
Since the Scots-Irish also entered Virginia through the port of Dumfries and went inland to the Shenandoah Valley, you must be careful that you don’t mix the two groups. The Scots come directly from Scotland–usually those parishes nearby Glasgow, and later Edinburgh. And the Scots-Irish come indirectly from Scotland through Donegal Irelandand other northern counties. Your favorite Virginia genealogist, Arlene Eakle http://www.arleneeakle.com
PS There is also some evidence that Scots came into Virginia from the Cape Fear River area of North Carolina and possibly through northern South Carolina. Stay tuned!