Norborne Parish was organized in early 1771 and served a large geographic area which today includes all of present-day Jefferson and Berkeley Counties as well as a large portion of Morgan County. The parish was created from the division of an earlier and larger Frederick County so that localized regions of colonial Virginia could expand the number of Anglican churches to keep up with increased settlement in the region.

The Anglican Church was the state sponsored and supported religion of Colonial Virginia and parishes were organized as administrative units for more localized areas. While the Church of England's hierarchy was centered in London, the power of local control was maintained by a parish vestry who had substantial power in local affairs. With the creation of Norbome Parish a new vestry, or local administrative body, was elected to carry out the taxation of the local community for the purpose of the development and maintenance of churches and church property. The first vestry of this parish includes many of the most prominent citizens of the area including Samuel Washington (senior warden), William Henshaw (junior warden), Robert Worthington (collector of tithes), Adam Stephen, Thomas Rutherford, James Keitz, George Cunningham, Magnus Tate, John Neville, William Baldwin, Morgan Morgan II, and Hugh Stephenson. These twelve men were given the responsibility over two existing churches one in Shepherdstown built 1769, and one in Bunker Hill built soon after the creation of Frederick County in 1738.

Rapid growth in the region during the second half of the 18th century brought a great deal of real estate development and eventual settlement to the Potomac and Shenandoah River Valleys. Shepherdstown (then called Mecklenburg) was established in 1762 when growth was occurring in the area. What is today known as Charles Town, is where the Washington family was developing a substantial agricultural empire. In order to accommodate a growing population, as well as to appease the ruling gentry tired of the long journeys to the two distant churches, the decision was made by the vestry to build a new mother church. Dates of construction for the new church are somewhat in doubt, but most sources estimate construction over a three-year period beginning in 1771 with completion in 1774. This places the new church in the precarious situation as being an elegant and costly symbol of English domination in the years leading up to the American Revolution.

Historically, the new church was named Norborne, Berkeley or Trinity with the name St. George being a later 19th romanticization which seems to have gained local acceptance and usage. Historical sources use the earlier names interchangeably and the earliest maps simply refer to it as the English church. This church was the central place of worship for Norborne Parish and was built substantially larger than the two other churches in the region. The combination of a T shaped floor plan with two stories of windows to illuminate a gallery section, gave the new church at least twice the seating capacity of other local places of worship. - NRHP, 6th December 2001