Harriett F Piatt was born c1851 in Virginia (probably Cabell County) to James Henry Piatt and Tabitha A 'Tempest' Morgan. She married on March 11, 1873, in Cooper County, Missouri, George C Mallott (or Malotte). George was born c1850 in Missouri.
Harriett's family was in Cabell County, Virginia in 1850 and is therefore the likely place of her birth in 1851. However, by the 1860 census the family had moved to Cole Hill P O, Palestine, Cooper County, Missouri. They had moved to Clear Creek Township, Cooper County, Missouri, by the 1870 census.
George and Harriett had the following known children:
James I Malott b: c1874 MO
Charles E Malott b: c1876 MO
Edith W Malott b: c1878 MO
Frederick L Malott b: c1880 MO
The family appeared on the 1880 census of White MCD, Benton County, Missouri:
Malott, George C age 29 born MO / WM / Married / Farmer / father born OH/mother born TN
Malott, Harriet (Wife) age 28 born VA / WF / Married / Keeping House / father born VA/mother born VA
Malott, James I (Son) age 6 born MO / WM / Single / father born MO/mother born VA
Malott, Charles E (Son) age 4 born MO / WM / Single / father born MO/mother born VA
Malott, Edith W (Daughter) age 2 born MO / WF / Single / father born MO/mother born VA
Malott, Fredrick L (Son) age 8/12 born MO / WM / Single / father born MO/mother born VA
Piatt, Cordelia (SisterL) age 24 born MO / WF / no marital status reported / father/mother born VA
This enumeration was taken from familysearch.org; no page number is available. Also in Benton County was Harriett and Cordelia's brother, Robert Piatt and family. Their father and other siblings were mostly in Clear Creek Township, Cooper County, Missouri.
I only had the 1880 abstracts of the Mallots because of Cordelia living with them. Therefore, if anyone else can supply any other enumerations or informations, I can add it here.