Hello Susan. I received your letter by mail. Yes, this is the correct family. William Henderson married Grizel/Grizelda Graham in Moffat, Dumfrieshire. One of their sons was John Henderson.He married Janet(Todd)Carlyle, the widow of William Carlyle of Doormount Moor, Dalton, Dumfrieshire. This couple had: Janet Henderson, b. 1770, m. John Davidson (of Castlebank, Dumfrieshire, came to Nova Scotia) Grizel/Grizelda Henderson, m. James King (in Truro, NS) James Henderson (twins...went to Jamaica) Robert Henderson (twins...went to Jamaica) John Henderson, b. Bondshaw, Dumfrieshire, Scotland, 1780 married there to Catherine Hall in 1802, came to Nova Scotia in 1805 settledat Truro, NS. By Catherine Hall he had: James Robert, William, Janet, John, Elizabeth and Barbara.
Another son of William and Grizelda (Graham) Henderson was Thomas Henderson. He married Margaret or Margery Hogg from Hoddam, Dumfrieshire, Scotland. This couple came on the "Lovely Nelly" in 1775 to Prince Edward Island, and then to Nova Scotia. Their children were Martha Henderson, Hannah Henderson, Thomas Henderson and John Henderson. Martha Henderson married William Campbell, the 1/2 brother of Wellwood Waugh, and lived at Pictou, NS. John Henderson worked on the Citadel in Halifax, NS for a while. Hemarried Nancy Johnson ca 1807 of River Philip, NS, daughter of Matthew and Ann (Ash) Johnson of River Philip, emigrants from Northumberland, England. By Nancy Johnson he had Thomas, Matthew, George and William. John and family settled in Tatamagouche, Nova Scotia.
A daughter of William and Grizelda (Graham) Henderson was Helen or Nellie Henderson. She married Wellwood Waugh, the Captain of the "Lovely Nellie." She was likely named for her father William Henderson's mother, Nellie/Helen (Murray) Henderson.
Another daughter, Janet Henderson, married David Harryson.
There appears to be a connection to other Henderson families in Nova Scotia such as the family of Robert and Margaret (Davidson) Henderson from Ecclefechan, Dumfrieshire, Scotland.
It is likely that the Hendersons left Scotland for religious reasons. They were staunch Methodists.