The Stephensons arrived at Charleston, South Carolina, from Scotland in 1773. Both William and James Stephenson and their two married sisters settled near Great Faols, South Carolina, in Chester County. .

From family trees written in early American bibles to birther conspiracy theories, genealogy has always mattered in the United States, whether for taking stock of kin when organizing a family reunion or drawing on membership—by blood or other means—to claim rights to land, inheritances, and more. And since the advent of DNA kits that purportedly trace genealogical relations through genetics, millions of people have used them to learn about their medical histories, biological parentage, and ethnic background. A Nation of Descendants traces Americans' fascination with tracking family lineage through three centuries. Francesca Morgan examines how specific groups throughout history grappled with finding and recording their forebears, focusing on Anglo-American white, Mormon, African American, Jewish, and Native American people. Morgan also describes how individuals and researchers use genealogy for personal and scholarly purposes, and she explores how local businesspeople, companies like Ancestry.com, and Henry Louis Gates Jr.'s Finding Your Roots series powered the commercialization and commodification of genealogy.

During his presidency, Jimmy Carter received a comprehensive analysis of his family's genealogy, dating back 12 generations, from leaders of the Mormon Church. More recently Carter's son Jeff took over the family history, determined to discover all that he could about his ancestors. This resulting volume traces every ancestral line of both Jimmy and Rosalynn Carter back to the original immigrants to America and chronicles their origins, occupations, and life dates. Among his forebears Carter found cabinet makers, farmers, preachers, illegitimate children, slave owners, indentured servants, a former Hessian soldier who fought against Napoleon, and even a spy for General George Washington at Valley Forge. With never-before-published historic photographs and a foreword by President Jimmy Carter, this is the definitive saga of a remarkable American family.