When Sarah Vail was born on 12 October 1730, in Morristown, Morris, New Jersey, United States, her father, Reverend John J. Vail Sr., was 45 and her mother, Martha Rose FitzRandolph, was 37. She married Isaac Jennings on 4 May 1748, in Elizabeth, Union, New Jersey, United States. They were the parents of at least 2 sons and 5 daughters. She died on 31 December 1810, in Hunterdon, New Jersey, United States, at the age of 80, and was buried in Readington Reformed Church Cemetery, Readington, Hunterdon, New Jersey, British Colonial America.