Here is a census record with the son from the marriage record above and with her mother as Abigail
"United States Census, 1880," database with images, FamilySearch(https://familysearch.org/ark:/61903/1:1:MZFJ-JDB : 13 September 2017), Ann Leonard in household of Philo Leonard, Pierrepont, St Lawrence, New York, United States; citing enumeration district ED 229, sheet 14B, NARA microfilm publication T9 (Washington D.C.: National Archives and Records Administration, n.d.), roll 0926; FHL microfilm 1,254,926.
From these two records, your search should concentrate around Pierpoint/Pierrepoint, New York