I'm researching a line of Hendersons that originally settled in Essex County, Mass. in 1730. (Thomas and Rebecca Henderson) There were several generations that remained in Mass., then moving on to New York. (Thomas married a Mary Anderson in 1743 in Essex County and had 5 children, four of whom lived past childhood) Like most family trees, there are a lot of holes. I am also at a loss to figure out how to trace the tree backwards. (I found one reference to Thomas Henderson who later married Mary Anderson as having been born in Clackmannanshire, Scotland, but the historical reference I have notates them coming from Ireland, making them Scotch-Irish.) Any thoughts?