Andrew moved to Missouri c1853 with his parents. Andrew's mother died in 1862 and his father married second to Sarah Ellen Smith who was the widow of George Lloyd and who had two daughters.
Andrew married on December 12, 1865, in Cooper County, Missouri, to Nancy Julia Blalock who was born in September of 1848 in Missouri. I note that Andrew's older brother, Robert Piatt, was married in 1862 to Mildred Blalock. Were these two Blalocks sisters?
Andrew and Nancy had the following known children:
Jennie V Piatt b: c1869 MO m: 26 Jul 1885 Henry Co, MO, Henry Bailey
George Piatt b: c1873 MO
Nora E Piatt b: c1874 MO
Sarah 'Sadie' Piatt b: Jun 1879 MO
While Andrew had married by the 1870 census, I did not locate him and his family in that census. But, did find them in Deer Creek, Henry County, Missouri, on the 1880 census as follows:
Piatt, Andrew age 40 born VA / WM / Married / father/mother born VA / cannot read/write
Piatt, Julia (wife) age 32 born MO / WF / Married / Keeps House / father/mother born NC
Piatt, Jennie (daughter) age 11 born MO / WF / Single / At Home / father born MO/mother born VA
Piatt, George (son) age 8 born MO / WM / Single / father born MO/mother born VA
Piatt, Nora E (daughter) age 6 born MO / WF / Single / father born MO/mother born VA
Piatt, Sarah (daughter) age 1 born MO / WF / Single / father born MO/mother born VA
This family was enumerated vol 14, ed 6 sh 10 (Ancestry.com image 30/52).
Andrew's father and step-mother and their family appeared in Boonville, Clear Creek Township, Cooper County, Missouri, in 1870 and Pilot Grove, Cooper County, Missouri in 1880. Jennie's marriage in 1885 indicates that the family stayed in that area until at least that time.
Who was the Tabitha A Piatt who married Charles M Brown September 09, 1885, in Henry County, Missouri a few months after Jennie V Piatt was married there? Was she the 'Tabitha A Piatt' daughter of Robert and Mildard Piatt of Benton County, Missouri from the 1880 census? That Tabitha was 10 years old and therefore 15 in 1885.
By the 1900 census of South Moniteau Township, Cooper County, Missouri, Andrew appeared as follows:
Piatt, Andrew J born Dec 1839 in WV / 60 on last bday
Piatt, Nancy J (wife) born Sep 1848 in MO / 51 on last bday
Piatt, Sadie (daughter) born Jun 1879 in MO / 20 on last bday
This family was enumerated at 25/58/15/7. A few houses away at 25/58/15/10 was George Piatt. Is this George born November 1872 in Missouri a son of Andrew and Nancy? He is not Andrew's brother, George Martin 'G. M.' Piatt, born March of 1873 in Missouri and enumerated in Blackwater Township on this census. Scattered throughout Cooper County was much of Andrew's extended family.