Catherine is listed as Kitty Ann on her son John's birth registration.  She is also shown as Kitty on her marriage entry which lists her place of birth to be America.    The 1901 census for Dryden lists her year of birth as 1843 and has her born in Ontario.  We know the family arrived in the US in June of 1838, only Andrew, Bell and John are listed on the manifest for the ship Courage, sailing from Londonderry Ireland and landing on June 21st, 1838.  Some accounts have her born in Philadelphia which is quite possible.

Ontario, Canada Deaths, 1869-1932 Record info about Kitty Ann McMillan
Name: Kitty Ann McMillan Death Date: 24 Oct 1918 Death Location: Kenora District Gender: Female Estimated Birth Year: abt 1843 Birth Location: Erin Twp Wellington Co,Ont