He was the first Sinkler in South Carolina. According to this site, his wife was Jane /GUERARD SINCLAIR.
"Eutawville takes its name from the Eutaw Spring. James Sinkler (died 1752) moved to America from Scotland in the early 1700s and settled near Bonneau, South Carolina. James Sinkler (1740–1800) and his wife Margaret Cantey moved to Upper St. John's Parish in 1785. William Sinkler (1787–1853), son of James and Margaret Cantey Sinkler and in turn his son, William Henry, owned Belvidere plantation in Eutawville. "
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