1683 Isaac Platt was taxed in Huntington, Long Island, New York. 
1691 On May 22, Isaac Platt wrote his will in Huntington upon Long Island within ye County of Suffolk & Province of N. York in America. The will mentioned a wife and 'five of my children': Jonas, John, Joseph, Jacob, and Mary. Son John Platt, brother Epenetus, and brother-in-law John Wood were named as executors. "In ye name of God Amen—I Isaak Platt of Huntington upon Long Island within ye County of Suffolk & Province of N. York in America lying under the afflicting hand of God yet having my perfect memory have made this my last Will & Testam't in manner and form following first I bequeath my soul to God my maker & redeemer & my body to ye earth from whence I was taken—Imp'mis—I give & bequeath to my son Jonas a House lott that I have lying between Samuel Woods & Jonathan Jarvesses with what advantage can be had thereunto at ye rear of the said lot & also one hundred pound right of commonage that I purchased of ye town of Huntington with all ye right & privileges thereunto belonging or ever hereafter shall belong to ye same and also two parcels of Meadow land lying on ye Southside of this Island one parcel on a neck called Swampawaan ye other parcel on a neck called by ye nameof Siases Neck all my right on the said Neck to remain to him & his heirs for ever and theafores'd upland likewise — Item—I give to my son Jonas a yoke of 3 year old white steers also if he abide with his mother & brethren until ye 29th of Sept. next & faithfully improve his time about their occasions then I do also give him ten bushels of wheat twelve bushels of Indian corn a quarter of an Ox called Darling that is now feeding, half an Ox hide tanned and as much upper leather as will make two pair of shoes — Item—I give & bequeath unto my wife the third part of all my other lands & meadows that I am possessed of during her natural life provided she continues a widow but if she marry to return to my three sons John Joseph & Jacob also I give & bequeath to my wife one third part of all my goods & chattels not yet given to continue for her only use comfort & disposal & if she desires it one room in my house entirely to her self as long as she continue a widow — Item — I give & bequeath to my daughter Elizabeth five pounds as it is valued in my inventory. Item—All the rest of my lands & meadows not yet given I give & bequeath to my three sons John Joseph & Jacob to be equally divided amongst them — Item—All the rest of my goods & chattels with ye valuation of buildings I give & bequeath amongst five of my children Jonas John Joseph Jacob & Mary to be equally divided amongst them after all my necessary charge is defrayed but if my son Jonas chance to die without lawful issue then his lands & meadows to be divided equally amongst the other three brothers also if John Joseph or Jacob die without lawful issue then their part that is deceased shall be equally divided between all these sons that are alive and if any of my children as aboves'd chance to die unmarried then their part of goods or chattels to be equally divided amongst ye rest surviving—Whereas it is before mentioned the valuation of buildings to be divided amongst five of my children—It is my will that ye buildings shall wholly remain unto my three sons John Joseph Sc Jacob the other two Jonas & Mary excluded as to ye building. My Executor that I appoint of this my last Will & Testam't is my son John Platt and for his assistance herein I request & appoint my loving brother Epenetus Piatt and my brother in law John Wood to be my overseers in trust to see all things herein contained done & performed according to all good intents herein contained In Witness whereof I have hereunto set to my hand & seal this 22d day of May in ye third year of his Mat'yes reign Anno Dom. 1691. The mark of Isaac x Platt. Signed sealed & published in presence of Joseph Bayley, Robert Kellam '' 
1691 On 31 July, Isaac Platt reportedly died and his will was probated on 22 October at Brookhaven, Suffolk County, Long Island, New York. 
 Charles T Gritman, Historical Miscellany (NY?: 1920?), left column, [AncestryImage].
 William S. Pelletreau, Early Long Island Wills of Suffolk County, 1691-1703 (1897), 53, of 51-5, [InternetArchive].
 William S. Pelletreau, Early Long Island Wills of Suffolk County, 1691-1703 (1897), 51, [InternetArchive].