I do not know for sure the parents of this Matthias Pettit. Several family trees on Ancestry.com link him as the oldest son of Mathias L. Pettit (1804-1859) and his first wife Hannah Ketchum, probably based mainly on their shared given name, but the main problem with that attribution is that Mathias Pettit and Hannah Ketchum had a son Matthias born 29 Oct 1849 who died at age 4 on 24 July 1854, and it would be highly unusual for he and Hannah to give another son the same name while the first was still living. Also, his birth place was given as Virginia on the 1850 census, and Matthias L. Pettit lived in Pennsylvania his entire life. Finally, Mathias L. Pettit and Hannah Ketchum were not married until 15 Oct 1829, and this Matthias was presumably born about 1828. (This third issue is less problematic, since it might be either that Mathias L. Pettit had an earlier wife, or that this Mathias was actually born after 1829.) Others attach him as a son of Charles Pettit Jr. (brother to Mathias L.) and Keziah Coe, but their son Mathias was born 23 Apr 1831 and married Ruth Penn. He and Ruth appear together in the 1870 and 1880 censuses of Greene Co., PA, when this Mathias and Helen were recorded in Braxton Co., West Virginia.

I am attaching him tentatively as a grandson of Azariah Pettit, based on the 1850 census, when he appeared with a presumed grandmother named Rebecca, who would be the right age to be Azariah’s widow. Also Azariah was living in Virginia by 1820.

The Braxton Co., West Virginia death register28 lists Mathias Pettit, age 73, born 1828, died 14 June 1901, cause of death kidney trouble, informant son.

1850 census of Marion Co., Virginia, eastern district, enumerated 27 Aug, lists on p. 58 as family #477/478:
Matthias Pettit, 22, farmer, b. Va; Laoma, 46, b. Penn; Rebecca, 76, b. Penn; Mary, 18, b. Va.

Probably Laoma is Matthias’ mother, Rebecca his grandmother, and Mary his sister.

1860 census of Marion Co., Virginia, district 1, enumerated 1 June, lists on p. 4 as family #24/21:
Mathias Pettit, 30, farmer; Helen M., 27; Sarah M., 2; George W., 1; Philadelphia, 3/12. All born in Virginia.

1870 census of Braxton Co., West Virginia, Lincoln township, enumerated 12 Aug, lists on p. 9 as family #61:
Pettit, Mathias, 45, farming; Helen M., 38; Sarah M., 12; George W., 11; Cordelia, 10; William N., 9; Caribel, 6; Ulysses G., 3; Charles S., 1. The three younger children born in West Virginia, all others in Virginia.

1880 census of Braxton Co., West Virginia, Otter district, enumerated 1 June, lists on p. 3 as family #22:
Pettit, Mathias, 57, farming, b. Va Pa Pa; Helen, 53, wife, b. Va Va Va; George, 21, son; Sarah, 22, dau; Carrah B., 15, dau; Willie, 19, son; Ulissus S., 13,son; Charley S., 11, son; Harrison, 8, son. George and Sarah born Va Va Va, the younger children born WVa Va Va.