Mahan Family Lineage 

Links in RED have been verified by me to have good biography sources worth reading.

Starting with the oldest, all familial relationships listed below will be in relation to to John Henry Mahan.  So James is John H. Mahan's 3rd Great Grandfather (great great great grandfather)

4th Great Grandparents (c 1720): Henry Mahan and Annie Syms. 
I have found no verifiable sources for these other than family trees created by other people.  Supposedly they were born in (what is now called) Northern Ireland not far from the monument in the picture above.

3rd Great Grandparents (c 1746): James Mahan and Mary Stuart-Mahan
They made the voyage from Ireland, died in Ohio

2nd Great Grandparents (c 1776): Rev. John Mahan and Susana Hillman
Born in Kentucky, died in Ohio

2nd Great Uncle (c 1772): Rev. Matthew Abraham Mahan
Born in Kentucky, died in Ohio

Great Grandparents (c 1824): David Mahan and Eliza Jane McGinnis
Born and Died in Ohio

Cousin of Great Grandfather (c 1801): John Bennington Mahan

Grandparents (c 1853): John Alexander Mahan and Mary Louisa "Lula" Moore
Born and Died in Ohio

Cousin of Grandfather (c 1824): Rev. Milton Mahin 

Parents (c 1876): William Earl Mahan and Elva Loretta Shock
Born in Ohio, Died in Florida

Sister (c 1917): Rev. Hon. Jennie Viola Mahan
Born in Ohio, Died in Florida

John Henry Mahan and Carrie Voy Ridenour
Born in Ohio, Died in Maryland and Florida respectively

Son (c 1940) John Barton Mahan

Son (living) William Lee Mahan Sr.

Son (living) Robert Lloyd Mahan

More to come