When Ira Jennings was born on 22 October 1783, in Buckland, Hampshire, Massachusetts, United States, his father, Ephraim Jennings, was 36 and his mother, Mariam Smith, was 36. He married Huldah Ann Mallory on 16 September 1809, in Buckland, Franklin, Massachusetts, United States. They were the parents of at least 2 sons and 2 daughters. He lived in Pierpont Township, Ashtabula, Ohio, United States in 1860. He died on 3 April 1868, in Pierpont, Ashtabula, Ohio, United States, at the age of 84, and was buried in City Cemetery, Conneaut, Ashtabula, Ohio, United States.