There are two possibilities that I have so far... 1) The family of Giles Johannes Fonda (b.1789) of Caughnawaga, NY moved to Hancock Co., Illinois in 1835.There were three sons, Hamilton (24), Henry (21) and John (13); and three daughters, two died young and Angeltie (23).Giles' grandparents were Douw Jellis Fonda and Maritje Vrooman. This could tie together the location and name that you are looking for... Isaac V. Fonda(ey) would be a fourth son, whose birthdate (1823) fits nicely between child #5 and #6. -or- 2) Douw Isaac Fonda (b. 1767) of Rensselaer Co. NY m. Gertrude Vrooman; no family information is available.Gertrude's mother's name is Delia which is also Isaac V. Fondey's daughter's name. I don't see any evidence of any migrations out of Saratoga from any of the immediate family... but it could fit. Also, the possible birthdate of 1804 would fit the Douw Fonda family (m.1788) and not the Giles Fonda family (m.1811).This is all just speculation... I have no supporting records.