Leffingwell Family Genealogy Forum
I am a descendant of Hannah Leffingwell, daughter of Michael who was the son of Thomas the immigrant.
One easy way to check some of the family history is by looking at all the historical societies and see how many have Leffingwell's listed. You will find them in several that I am aware of, such as the Daughters of Founders and Patriots of America, the DAR, etc.
This makes for very interesting reading and you can always write and request the records from the society.