I was doing some housekeeping, cleaning up source citations I wrote early in my research, and noticed again how useful the Virginia Transportation Research Council (VTRC) series of 18th c. county road orders had been. I downloaded half a dozen of the reports in PDF form years ago and hadn't checked their site recently.
The VTRC website lists eighteen reports derived from county court records that cover time frames ranging from very brief (1763-1764 for Culpepper County) to half a century (1750-1800 for Orange County). All are in PDF form, indexed, searchable and can be saved. There are also reports available on early roads and road markers.
None of the reports provided definitive evidence for the families I was researching, but in conjunction with other records they helped place families or individuals in a specific spot at a specific time. For migrating families this has been especially helpful. This entry, for example, from the Spotsylvania County report, was one of the earliest dates I found for John Mulkey in Virginia.
7 July 1724 O.S., Page 80
Ordered that John Mulkey be overseer of that [missing] of the road that goes to William Eddins below the orchard of white Oaks, from thence down to the fall landingIf you are researching 19th c. Virginians it might be worth a look.
Source: Pawlett, Nathanial Mason, Spotsylvania County Road Orders, 1722-1734 (Charlottesville, VA: Virginia Highway & Transportation Research Council, 1985, revised 2004), 9; digital images, VTRC (http://www.virginiadot.org/vtrc/main/online%5Freports/pdf/85-r17.pdf : accessed 18 Jul 2010).