I've added some census data links to "source records" for John Hans (1825-1899) on OneFamilyTree on www.ancestry.com.
I'm a descendant of John Hans of Rochester &/or Irondequoit New York (Monroe County), via his son Frank Hanss Sr. who lived much of his adult life in Iowa.
I've notice others adding to this tree and thought this information might be of interest: spelling of this name has varied in the census records, and has been misread when indexed into www.ancestry.com, I believe -- it took some time for me to locate these records and I would like to share this information:

1880 Census, State: New York; County: Monroe; City: Rochester.
John Hans is how I would read the name of the head of household, and that is how it is indexed.
Wife: Mary. Children: Kate, Barbara, Helen, Jacob, Frank, Molie, John, Edward, Charles, Agie
Frank spelled his name Hanss here in Iowa; I believe his brother John also spelled it that way in New York.

1870 Census, State: New York; County: Monroe; City: Irondequoit:
John Hone is how the name has been entered into the computer index -- he's head of household. I would read the name as John Hons. His wife is named Barbary (not Mary, but her maiden name was Barbric or Barberick, or Barbrick) and the ages are very close; children's names listed are: Cathern, Mary, Barbary, Lona/Lana, Jacob, and Frank : some name spelling variation but age information corresponds well to 1880 Census.
I believe the city of Rochester New York annexed parts of Irondequoit over the years -- I doubt if the family moved: census notes indicate the family lived on Bay Street.

1860 Census; State: New York; County: Monroe; City: Irondequoit.
Head of household's name is indexed as: John Hautz -- I would read it as John Hantz
Wife: Mary; Children: John, Catherine, Mary. It looks to me like the their first son John may have died relatively young, and and they later named a younger son John.
There is another person living in the household: Agnes Barberick, who is 62 years old; wife Mary's maiden name is Barberick / Barbrick / Barbric, so this may be a mother-in-law to John Hans, or possibly some other close relative of his wife's.

Also in the 1860 census for New York State, Monroe County, Irondequoit:
Jacob and Catherine Hantz, both age 73, born in Baden (Germany) -- see 1850 census info below - I think these two are John Hans's parents:

1850 Census, New York State, Monroe County, Irondequoit:
Head of Household: Jacob Hance, wife Catherine, children John (age is close), Mary E and Margaret (these two may be twins -- same age). All were born in Germany.

Please email me at bluedode@yahoo.com -- I'm using ancestry.com at our library and will not receive email replies to denlib@frontiernet.com

I have some pictures of people in this family, some of whom are identified and some not, so am reasonably sure I'm a descendant from this family. If anyone would like to help me identify some of these photos, or would like to know if their ancestors might be in them, please let me know at email: bluedode@yahoo.com

Thank you for listening!

Dorothy Lueck