The ancestry of Capt. Henry Carroll of St. Mary's County (d. 1776) is unproven. His second son is named Michael Brown Carroll. An earlier Michael Brown Carroll, a surgeon in a British Regiment of Foote, was given a parole (a pass) to visit Charles Carroll of Carrollton during the Revolutionary War, with this earlier Surgeon Michael Brown Carroll referencing Charles Carroll of Cork in his will. It is certainly possible that Capt. Henry Carroll of St. Mary's County is somehow related to the Michael Brown Carroll, surgeon and Charles Carroll of Cork, Ireland, apothecary -- though it is still unproven. A member of the family of Charles Carroll of Cork, apothecary, settled in Canada.

Back in Ireland, a descendant of Charles Carroll of Cork, apothecary, sent an elderly Charles Carroll of Carrollton in Maryland (who at that time was a national hero) a letter, stating that they both used a similar family crest, and asking how they might be related. Charles Carroll of Carrollton answered that he did not know. [see item 17 in the Miscellaneous subseries, Digital Files]