I think your best place to start would be to obtain their marriage details this may give you more clues to their parents.

Scotlands People is the best site but it is pay per view, on a quick free search there doesn't seem to be a marriage for William Robertson to Elizabeth Margaret Muir but there are two marriages for William Robertson to a Muir in time frame 1850-1870

Thank you, I will see if I can find the two you saw. I have not been able to find one so far on Ancestry or Family Search.............

Ancestry doesn't show Scotland marriages I'm afraid, and the only way I know is through Scotlands People.

Is this your William in 1900 US Census

1900 United States Federal Census about Wm Robertson
Name: Wm Robertson
Age: 56
Birth Date: Dec 1843
Birthplace: Ireland
Home in 1900: Philadelphia Ward 22, Philadelphia, Pennsylvania
[Philadelphia, Philadelphia, Pennsylvania]
Race: White
Gender: Male
Immigration Year: 1866
Relation to Head of House: Head
Marital Status: Married
Spouse's Name: Margaret Robertson
Marriage Year: 1862
Years Married: 38
Father's Birthplace: Ireland
Mother's Birthplace: Ireland
Occupation: View on Image
Neighbors: View others on page
Household Members:
Name Age
Wm Robertson 56
Margaret Robertson 57 b May 1843 Scotland
Hugh Robertson 22 b May 1878
Florence Robertson 12 b Dec 1887

Address at time of Census 8619 Sullivan Street

According to the Census William arrived in US in 1866 and is Naturalised they have 10 children 7 alive, Williams occupation Landscape Gardner and Hugh is also Landscape Gardner.

1910 US Census

1910 United States Federal Census about William Robertson
Name: William Robertson
Age in 1910: 69
[64]
Birth Year: abt 1846
[1841]
Birthplace: Ireland
Home in 1910: Philadelphia Ward 22, Philadelphia, Pennsylvania
Race: White
Gender: Male
Immigration Year: 1870
Relation to Head of House: Head
[Self (Head)]
Marital Status: Married
Spouse's Name: Margaret Robertson
Father's Birthplace: Ireland
Mother's Birthplace: Ireland
Neighbors: View others on page
Household Members:
Name Age
William Robertson 69
[64]
Margaret Robertson 65
Jeannette Robertson 43 b1867 Scotland
Hugh Robertson 28
Florence Robertson 20

address at time of census 8215 Norwood? Street

Williams occupation Paper Maker shows his arrival as 1870 Naturalised
Hugh occupation Slate & Tile Roofer
Florence occupation Telephone Operator
Jeannette no occupation

In 1920 Census William is living with Florence & her Husband Nelson Maxwell and their children

1920 United States Federal Census about William Robertson
Name: William Robertson
Age: 80
Birth Year: abt 1840
Birthplace: Ireland
Home in 1920: Philadelphia Ward 22, Philadelphia, Pennsylvania
Race: White
Gender: Male
Immigration Year: 1885
Relation to Head of House: Father-in-Law
Marital Status: Widowed
[Widow]
Father's Birthplace: Scotland
Mother's Birthplace: Scotland
Able to Read: Yes
Able to Write: Yes
Neighbors: View others on page
Household Members:
Name Age
Nelson Maxwell 35
Florence Maxwell 32
Ethel A Maxwell 7
Kathleen M Maxwell 3 [3 6/12]
William Robertson 80 father in law
Hugh Robertson 40
Janet Mac Kenzie 56 (Jeannette)

Address is 263 West? Duval Street Hugh is still a Roofer and it looks like Jeannette is now Janet and is married to a MacKenzie.

Williams arrival is shown as 1885 and Naturalised in 1895 he is Widow, Elizabeth Margaret or Margaret has presumably died between 1910 and 1920 Census.

You may be able to track down his naturalisation although his arrival date varies between 1866 and 1885 which isn't helpful.

Jeannette's marriage to George H MacKenzie

Philadelphia, Pennsylvania, Marriage Index, 1885-1951 about Jeannette Robertson
Name: Jeannette Robertson
Gender: Female
Spouse Surname: MacKenzie
Spouse Gender: Male
Marriage Place: Philadelphia, Pennsylvania, United States
Marriage Year: 1910
Marriage License Number: 259964
Digital GSU Number: 4141911

Philadelphia, Pennsylvania, Marriage Index, 1885-1951 about George H MacKenzie
Name: George H MacKenzie
Gender: Male
Spouse Surname: Robertson
Spouse Gender: Female
Marriage Place: Philadelphia, Pennsylvania, United States
Marriage Year: 1910
Marriage License Number: 259964
Digital GSU Number: 4141877

If you can get a copy of the certificate it may give you more clues on her and her father.

I haven't been able to find any Scotland Census at the moment for William they may have migrated between Jeannettes birth in 1867 and the 1871 Census but anything is possible. There are hundreds of Robertson so narrowing down her birth will be tricky, it will depend on how it was registered ie, Jeannette/Jeanette/Jenet/Jennet and the list goes on. If you can find out where her parents were married that may narrow the search.

Thank you, I do have this information on my Ancestry Tree Maxwell/Robertson. Florence was my grandmother, Kathleen Maxwell, my mother. I'm starting to think they may not have all come over together. My mother told me Jeannette & Alexander were born in Scotland and her mother Florence and the others were born in Chestnut Hill,PA & Germantown,PA . My great grandfather was the gardner at the Pepper Estate for a few years & won awards at the Philadelphia Flower shows. I have news paper articals talking about him. The family story is my great grandfather William was a gardner in Scotland for my great grandmother Elizabeth Margaret Muir's family home, they fell in love, the family did not want her to marry a gardner, she did and they moved to USA a few years later. My mother & all her family have passed now, so getting more info is up to me to figure out. Thanks for helping me, I love the search but sometimes I feel like I hit a brick wall. Joy

The joys of family research, I have quite a few brick walls and great big black holes which my family seem to disappear into.

It will really help your search if you can get a copy of the marriage certificate she may have used Margaret instead of Elizabeth Margaret as she is Margaret in the US Census.

Hello, your right, she may have, I'll see what I can find. I wish I knew if William had a middle initial, that might help too. Let the hunt go on and on & on! :) Joy