Can anyone help me break this wall?

Question

Hello i am trying to figure out

who my 3rd great grandmas parents were

all i know is she married john mcmillen born around 1813-1815 ireland but i think he birth place may been in ontario,canada  i think prince edward but i could be wrong

all i know is henrietta or harriett married him not sure where yet

they both lived and died in ontario,canada

her last name was free

i know she had a first marriage to a guy name john eaton

and he died then she married john mcmillen

any help will be appreciate it

Answer 1

John Mcmillan

Ontario Deaths and Overseas Deaths, 1939-1947

Name	John Mcmillan
Event Type	Death
Event Date	07 Oct 1883
Event Place	Lochiel, Glengarry, Ontario
Gender	Male
Age	69
Birthplace	Canada
Birth Year (Estimated)	1814

CITING THIS RECORD

"Ontario Deaths, 1869-1937 and Overseas Deaths, 1939-1947," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:JDKJ-7Y8 : accessed 6 April 2016), John Mcmillan, 07 Oct 1883; citing Lochiel, Glengarry, Ontario, yr 1883 cn 15861, Archives of Ontario, Toronto; FHL microfilm 1,853,240.

Answer 2

John Mcmillen
Father
Ohio Births and Christenings, 1821-1962
spouse:    Harriett Mccullough
child:    Rachel Mcmillen        

John Mcmillen
Father
Ohio Births and Christenings, 1821-1962
spouse:    Harriett Mccullough
child:    Margaret Mcmillon

John Mullin
Father
Canada Births and Baptisms, 1661-1959
spouse:    Henrietta Milligan
child:    Carrie Vaeeita Mullin        

John Mullin
Father
Ontario Births and Baptisms, 1779-1899
spouse:    Henrietta Milligan
child:    Carrie Vaeeita Mullin        

John Mullin
Father
Ontario Births, 1869-1911
spouse:    Henrietta Milligan
child:    Carrie Valletta Mullin