Two grandsons of President John Tyler (1841-1845) are alive today.

I am fascinated by time telescoping and here's one to beat all. Heir-Raising Experience from Snopes.

Even if John Tyler may not be remembered kindly by history for his political efforts, he is nonetheless notable today for an unusual aspect of his non-political life: though Tyler was born in the 18th century and died in the middle of the 19th century, two of his grandsons are alive today, more than a decade into the 21st century. It's a circumstance many people find unbelievable — that there are two people living in the United States today who are the direct offspring of children born to a man who not only served as President of the United States twenty years before Abraham Lincoln did, but who was a contemporary of such titanic early American political figures as Henry Clay, Daniel Webster, and John C. Calhoun, and was himself born when George Washington was President.

This remarkably short line of ascendancy is due to a confluence of factors that are not common in modern American society but once were not so unusual: men (particularly widowers) marrying much younger women late in life and fathering large numbers of children. John Tyler fathered fifteen children, more than any other U.S. president: eight with his first wife, Letitia Christian Tyler (who was his own age), and seven more with Julia Gardiner Tyler (a woman thirty years his junior) whom he married two years after the death of Letitia. Five of those children lived into the 20th century (the youngest, Pearl Tyler, was still alive after the end of World War II and finally passed away in 1947), and one of them repeated the pattern of his father. John Tyler's thirteenth child, Lyon Gardiner Tyler (1853–1935), had three children with his first wife, Anne Baker Tucker Tyler, and three more with his second wife, Sue Ruffin Tyler (a woman thirty-five years his junior), whom he wed a few years after Anne's death, when he was nearly 70. One of those latter three children died in infancy, but the other two, Lyon Gardiner Tyler, Jr. and Harrison Ruffin Tyler (both born in the 1920s), are still with us today, living grandsons of the 10th President of the United States.