In 1860 David and father David Mckinley b IRE abt 1830-31 living in same family/household.Did not locate a female McKinley in this household, possibly his mother died?
This possible father is found in later census data living in same area as David jr.listed as widowed in 1880.1870 Census seems to be employees of a Charity Hospital - so no marital status etc is given.
There is a David Mckenley, cabinetmaker,b abt 1830 IRE in the 1850 NY census living with his large family from IRE - another ??
Requires lots more research but might be a start.
Not my family, good luck.
U S Census, 1900 ED 127 Rosendale Township (north part excl. Rosendale vill.), Ulster, NY
headDavid MckinleyM 43 NY/IRE/IRE marr abt 1881 wifeMartha Mckinley F 35 Feb 1865 NY/Ire/Ire 13 children 9 living sonHarry Mckinley M 17 New York dauJessie Mckinley F 14 New York sonLawton Mckinley M 11 New York sonFrank Mckinley M 9 New York sonWilliam Mckinley M 7 New York dauMartha Mckinley F 5 New York dauGrace Mckinley F 3 New York sonGeorge Mckinley M 0 New
U S Census, 1880 Rosendale, Ulster, NY (Household of Sarah McGlodin) otherDavid Mc KinlyM 23 NYLaborer
United States Census, 1880 South Rondout, Ulster, NY name : David Mc Kinley Male age: 50Widowed occupation : Cabinet Maker birthplace : Ireland birthdate : 1830
U S Census, 1870 New York City, ward 19, NY Address: Charity Hospital Blackwells Island name: David Mc KinleyCabinetmaker Male Age 40 est birth year: 1830Ireland
USCensus, 1860 2d Division 7th Ward The City Of New York, NY
name: David Mc Kinley Maleage: 29 years est birth 1831 birthplace: Ireland gender: Male page133 family number: 951
name: David Mc Kinley Male age: 4 yearsestbirth year: 1856 birthplace: New York page: 133 family number: 951
US Census, 1850 New York City, ward 16, New York, NY Archibald Mckenley M 45 IRE Ellen Mckenley F 47 IRE David MckenleyM 20 IRECabinet maker Daniel Mckenley M 26 IRE Samuel Mckenley M 20 IRE Sarah Mckenley F 18 IRE Margaret Mckenley F 15 IRE Archer Mckenley M 12 NY John Mckenley M 7 NY