Amazingly, 1770 marks to formation of both Botetourt County and Botetourt (Anglican) Parish (now called St. Mark's).  An acre of land in Fincastle, the County seat, was designated to be used by the Established Church of England for a church building and a cemetery.  The building erected was on Back Street, the site of the present Presbyterian Church, and was supported by the Anglican colony, not members of the church.

As a result, the next few years were stormy ones for the small Anglican congregation.  With the American Revolution came a loss of support for the Established Church.  The church building and its land in Fincastle gradually came under Presbyterian influence. Although the congregation lost its building, services were continued in the homes of its members.  From about 1830, many of these services were conducted by visiting clergy at "Grove Hill," home of General James Breckinridge near Fincastle.  The little group began to revive, and in 1837 the Vestry bought land on the west side of Roanoke Street in Fincastle for the sum of $175.  (The original deed may be seen in the vestibule of St. Mark's.)

The brick building shows the Gothic influence in its pointed arches over the doorway and windows; however, the interior of the church is traditionally colonial in style.  There has been no basic change to the original structure.  Various rearrangements of the pews have occurred over the years, including the  installation of central heating, air conditioning, and the installment of the present baptismal font.  Recently, several pews were repositioned to enlarge the choir area.  The acorn hinges on the pew doors are the originals.  The electrified lighting fixtures are probably also original to the building.  The Georgian communion service dates from the early church and was preserved during the Civil War by the Breckinridge family. The church is an historical landmark. Growth of the congregation over the years has led to the purchase of adjoining land and structures.  The Parish Hall addition to the original church was completed in 1966.  A major development in 2004 was the purchase of property at the corner of Roanoke and Herndon Streets.  Existing structures there have been remodeled to accommodate Sunday School and meeting rooms, offices and reception areas, a Youth Center, and St. Mark's outreach programs.  The Botetourt County Food Pantry which serves all families of the county is now housed in the addition and served by volunteers from St. Mark's as well as many other Fincastle churches.