Loyal's gravestone says 1863-1938 (see page 54 of Lester Binnie's Cemetery Records of Paw Paw and Pleasant Townships, Wabash County, Indiana), but 1900 census disagrees (see below.) The 1870 and 1880 censuses are not much help; they list him as respectively 6 and 16. The censuses were taken in early August, so if he was born in 1863 he would have been 6/16 nearly 7/17, if he was born in 1864 he would have been 5/15 nearly 6/16. Either way, he could have been listed as he was.

1900 census of Wabash Co., IN, Chester twp, enumerator's district 114, lists as family #648:
Ohmart, Loyal, Aug 1864, 35; Sarah, Aug 1867, 32; Ethel, Jan 1891, 9; Mabel, Apr 1899, 1; married 10 years, with 2 children both living. All family members born in IN; I neglected to note their parents' birthplaces.

Sarah's gravestone says 1870-1951 (see page 54 of Lester Binnie's Cemetery Records of Paw Paw and Pleasant Townships, Wabash County, Indiana), but 1900 census has her birthdate as Aug 1867.

The Ohmart genealogy I got from Verle Ohmart has a birth date of 1 Aug 1870; he did not record his sources. Since his records also had an exact date of death, the birth may have been from an obituary.