Family History and Genealogy Resources by Surname
Sewall Surname Origin
Probably from sea and wall, a structure of stone or other materials intended for a defense or security against the sea. This name, though seemingly local, may have various significations; suil, in the Gaelic, is a willow; suail, small, inconsiderable. Su, south, and wold, wald, wild, well, an uncultivated place, a wood, a plain, a lawn, hills without wood: Suwold, Suwall, Suwell.
Source: An Etymological Dictionary of Family and Christian Names With an Essay on their Derivation and Import; Arthur, William, M.A.; New York, NY: Sheldon, Blake, Bleeker & CO., 1857.
Sewall Surname Meaning and Family Facts
There is more to Sewall family history than the origin of your surname:
A Sewall Family History Thought:
'If you would not be forgotten,
As soon as you are dead and rotten,
Either write things worthy of reading,
Or do things worthy of writing.' --Benjamin Franklin, May 1738