His grandfather James Foster was the eldest son of Alexander Foster, who emigrated from county Londonderry, Ireland, about the year 1725. Most comprehensive family history was written by Evelyn Foster Morneweck, Stephen's niece, and published in 1944. The two-volume book can be read online.

Chronicles of Stephen Foster's Family, vol. 1

Chronicles of Stephen Foster's Family, vol. 2

Read the first chapter of vol. 1.

~Masato