Here is what I found... hope this helps a little!
1860 Census
Name: George Miller
Age: 9
Birth Year: abt 1851
Gender: Male
Birth Place: Pennsylvania
Home in 1860: German, Fayette, Pennsylvania
Post Office: Masontown
Family Number: 22
Household Members:
David Miller 43 (Head; Occupation: Blacksmith)
Elizabeth Miller 39
Thos Miller 18
Martha Miller 16
Susanna Miller 14
Joseph Miller 12
George Miller 9
Elizabeth Miller 9/12
Source Citation
Year: 1860; Census Place: German, Fayette, Pennsylvania; Roll: M653_1109; Page: 350; Image: 301; Family History Library Film: 805109
Enumeration Date: 18 July 1860
1870 Census
Name: George Miller
Age in 1870: 18
Birth Year: abt 1852
Birthplace: Pennsylvania
Home in 1870: German, Fayette, Pennsylvania
Race: White
Gender: Male
Post Office: Masontown
Household Members: (All listed as being born in PA)
David Miller 53 (Head; Occupation: Blacksmith)
Elizabeth Miller 49 (Occupation: Housework)
Thomas Miller 29 (Occupation: Blacksmith)
George Miller 18
Elizabeth Miller 11
Eliza Miller 10
Source Citation
Year: 1870; Census Place: German, Fayette, Pennsylvania; Roll: M593_1342; Page: 195B; Image: 395; Family History Library Film: 552841
Enumeration Date: 5 Aug 1870
1880 Census
Name: George H. Miller
Age: 26
Birth Year: abt 1854
Birthplace: Pennsylvania
Home in 1880: Uniontown, Fayette, Pennsylvania
Race: White
Gender: Male
Relation to Head of House: Self (Head)
Marital Status: Married
Spouse's Name: Ida M. Miller
Father's Birthplace: Pennsylvania
Mother's Birthplace: Pennsylvania
Neighbors: View others on page
Occupation: Tinner (a tin miner or tinsmith)
Household Members:
George H. Miller 26
Ida M. Miller 22
Clyde B. Miller 1
Source Citation
Year: 1880; Census Place: Uniontown, Fayette, Pennsylvania; Roll: 1130; Family History Film: 1255130; Page: 420D; Enumeration District: 053; Description: East Ward Uniontown; Image: 0373
1900 Census
Name: G H Miller
Age: 46
Birth Date: Jul 1854
Birthplace: Pennsylvania
Home in 1900: Uniontown, Fayette, Pennsylvania
Race: White
Gender: Male
Relation to Head of House: Head
Marital Status: Widowed
Father's Birthplace: Pennsylvania
Mother's Birthplace: Pennsylvania
Household Members:
G H Miller 46
Clyde B Miller 21
George H Miller 12
Mary L Miller 10
Muriel Miller 8
Mary Jane Shaw 81 (aunt)
Margaret Marker 23 (relationship to head: none listed)
Source Citation
Year: 1900; Census Place: Uniontown, Fayette, Pennsylvania; Roll: 1411; Page: 18A; Enumeration District: 0068; Description: Uniontown Borough, ward 4; FHL microfilm: 1241411
From FindAGrave
Name George Horace Miller
Birth Date 4 Jul 1854
Birth Place Brownsville, Fayette County, Pennsylvania, USA
Death Date 7 Jul 1905
Death Place Fayette County, Pennsylvania, USA
Cemetery Oak Grove Cemetery
Burial or Cremation Place Uniontown, Fayette County, Pennsylvania, USA
Only citation / source I could find for his marriage to Ida Springer is as follows:
Marriage - 7 July 1877, Brownsville, Fayette County, Pennsylvania, USA
Source Information
Title: Genealogical and Personal History of Fayette and Greene Counties, PA
Author: J. W. Jordan and James Hadden, Editors
Call Number: F157 F2 J8 v.3
Medium: Book
Publisher: Lewis Historical Publishing Company, New York - 1912
Page 784
From Ancestry - may or may not be accurate
Children are listed as:
Clyde Barto Miller 1878–1960
Ralph Earl Miller 1881–1888
George Horace Miller 1887–1968
Mary Lincoln Miller 1889–
Muriel Marie Miller 1891–1976