Gray Genealogy diagram in possession of Donald Edward Gray states that John Gray married 1st Ann
McKinney, then 2nd Margaret Miller.

1850 Census - Butler County, Pennsylvania
South Butler Town - 30 Sep 1850

  153 153
  Thos. Gray   31 M Farmer Penn
  Elizabeth A. 33 F        Penn
  Christina     8 F        Penn
  Mary          5 F        Penn
  John          3 M        Penn
  Henry C.   7/12 M        Penn

  155 155
  John Gray    23 M        Penn
  Ann          24 F        Penn

1860 Census - Butler County, Pennsylvania
Forward TWP - 15 June 1860

  201 203
  John Gray   33 M Farmhand  250 Penn
  Ann         33 F               Do
  Winfield     9 M               Do
  Lydia        7 F               Do
  Thomas       4 M               Do
  Mary J.      2 F               Do
  Martha E. 1/12 F               Do

1870 Census - Mercer County, Pennsylvania
East Lackawannock - 8 April 1870

  131 123
  Grey, John     43 M W Carpenter      300 Penn
  Margaret       44 F W Keeping House      Penn
  Thomas         14 M W At Home            Penn
  Lizzie         12 F W At Home            Penn
  France, Kate   20 F W School Teacher 150 Ohio