Margaret came to America on the ship Abigail about 1635. She is listed in Seventeenth Century Colonial Ancestors. Several researchers have assumed that Margaret left her husband going to America with her sister and brother-in-law John Winthrop, Jr and her two daughters. Others state that John Lake died which prompted her move to America with her daughters. This is based on a letter written to John Winthrop, Jr. in January 1661/2 in which she wrote "...concerning my husbands death and how hee ended his dayes." Since Margaret lived with John Winthrop Jr. when she reached America in 1635 it is a puzzle why she was prompted to write to Winthrop about his death 26 years later. One researcher believes that he died just prior to Margaret having written Winthrop.

Margaret spent her later years at Ipswich, Massachusetts living with her daughter Martha Lake Harris. Her brother-in-law Deputy Governor Samuel Symonds also resided there. Researchers cite her death as 24 September 1672 however this is when her estate was probated leaving her daughter Hannah Gallup land in New London, Connecticut.

Margaret Reade is an ancestor of President George Walker Bush through daughter Hannah Gallup.