1870 Emmitsburg, Frederick, MD
John Mahue, b. PA, 27, carpenter
Cecelia, b. MD, 25
W. M. H. Heags, b. PA, 35, farm laborer
Barbery, b. MD, 31
John Smith, b. MD, 9
I think John was an orphan they took in or adopted. You'll have to look up the Maryland adoption rules to see if you can get access to those records. Also there should be court guardian records for John after his parents died.
1880 Cumberland, Adams, PA
William Heagy, b. PA, 48, farmer
Jennie B., b. PA, 43
John, b. PA, 18
1900 Taneytown, Carroll, MD
John W. Haegey, b. MD, June 1861, M18yrs, well digger
Emma J., b. PA, Oct 1861, 6/4 ch
Carrie E., b. PA April 1891
Clarence A., b. PA, Jan 1894
I found John's death certificate. It shows that he was born 28 June 1861 in Westminster Ind. There isn't a Westminster Indiana. I think this was an error. When a person dies, the Informant provides birth and parent information. It isn't checked out or verified.
I'd say his parents were John and Mary Ann Smith. Did you look for them in Frederick County, Maryland?
Also what did his obituary say about his parents? Successful Searching!