No one has specifically determined the single individual who migrated to USA. Speculation is that J. McLaughlin migrated in early 1700's, or his father. He was born abt 1730. Either he or his father probably arrived at the Chaleston SC (or nearby) port of entry. He has at LEAST 3 sons, who each enlisted and fought in the Rev War. I descend from two brothers Jacob and John. I have much more data on McLaughlin/McGlothlin lineage if you're interested.
Do you have the McGlothlin line further back than Henry? Is this the Henry Lewis McGlothlin born 1840 in Russell Co VA?