The location of the building is indicated by a notation on Buckner's
plat of the port town: "The fourth course (runs) down along by the Gutt
between Geo: Andrew's & the Court house to Potomack Creek." A glance at
the plat (fig. 2) will disclose that the longitudinal boundaries of all
the lots south of a line between George Andrews' "Gutt" run parallel to
this fourth course. Plainly, the courthouse was situated near the head
of the gutt, where the westerly boundary course changed, near the end of
"The Broad Street Across the Town." It may be significant that the
foundation (Structure B) on which John Mercer's mansion was later built
is located in this vicinity.
In or about the year 1718 the courthouse "burnt Down,"[32] while it was
reported as "being become ruinous" in 1720, with its "Situation very
inconvenient for the greater part of the Inhabitants." It was then
agreed to build a new courthouse "at the head of Ocqua Creek."[33] Aquia
Creek was probably meant, but this must have been an error and the "head
of Potomac Creek" intended instead. Happel shows that it was built on
the south side of Potomac Creek. Thus, the burning of the Marlborough
courthouse in 1718 merely speeded up the forces that led to the end of
the town's career.