Of Abraham and Mary Todd Lincoln’s four sons, only one lived to maturity. Robert Todd Lincoln (1843 – 1926) married Mary Harlan (1847 – 1937) in 1868. They had three children, Jessie, Abraham, and Mary. Abraham ("Jack") Lincoln died in 1890 at the age of 17. Mary (1869 – 1938) became the wife of Charles Bradley Isham in 1891. Their son, Lincoln Isham, born in 1892, died in Dorset, Vermont, in 1971. His marriage to Leahalma Correa was childless. Jessie (1875 – 1948) eloped with a college football player and sportsman from Mount Pleasant, Iowa, Warren Wallace Beckwith, in 1897. They had two children, Mary Lincoln Beckwith and Robert Lincoln Beckwith, before their divorce in 1907. Jessie lived with her parents until she remarried in 1915; her second husband was an explorer and geographer named Frank Edward Johnson. The marriage was childless and ended in divorce in 1925. The next year she married Robert J. Randolph, by whom she had no children.
Mary Lincoln Beckwith (1898 – 1975), Abraham Lincoln’s great-granddaughter, never married. Her brother Robert Lincoln Beckwith (b. 1904 ), twice married (to Mrs. Hazel Holland Wilson and Annemarie Hoffman), but had no children either. Like most Lincoln descendents before him, he was wealthy, led a quiet life and avoided the public gaze. He died in 1984. He was the last direct descendent of Abraham Lincoln.
From The Encyclopedia of Abraham Lincoln by Mark Neely, Jr.