- Born: 16 April 1831 Union Co, Kentucky
- Died: 7 May 1878 Fairfield, Wayne Co, Illinois
- Burial: Hearn Cemetery, Wayne Co, Illinois
- Civil War: Union Army, 29th Illinois Infantry, Company D; engaged in Battle of Shiloh, Siege of Corinth, Battle of Corinth. POW in Holly Springs, MS.
- Isaiah enlisted in the 29th Illinois Volunteer Infantry, Company D for 3 years 14 Aug 1861 - 1 Jan 1865. Enlisted at Cairo, IL.
- He was engaged in the Battle of Shiloh 6 & 7 April 1862; Siege of Corinth/Battle of Corinth 3 & 4 October 1863. The regiment was captured at Holly Springs, MS on 20 Dec 1862, confined in POW camp at Richmond, VA, then paroled, and returned to active duty.
- Military description books describe him as: Light complexion, light hair, blue eyes, being 5'4" tall.
- He was discharged as an infantry private for reason of expiration of terms of service.
- There is some evidence that he was raised in the Ellison household rather than the Segars household. His name appears in census records as living in the James Smith Ellison [b. 7 Oct 1797 NC (1 census states VA); d. 20 Aug 1864 Gallatin Co., IL; md. Drewsilla] household.
- 30 October 1865 Fairfield, Wayne Co, Illinois
- ♂stillborn son
- ♀stillborn daughter
- ♂James Jesse Segars (1866- )
- ♂Joseph Ellsworth Segars (1868-1931)
- ♀Martha Elizabeth Segars (1870-1945)
- ♀Nancy Jane "Nannie" Segars (1872- )
- ♀Sarah Alice Segars (1874-1928)
- ♀Nora Ann Segars (1877- )
- ♂Isaiah Franklin "Frank" Segars (1879-1964)