I am from New Zealand & am trying to trace my great grandfather's ancestors. I have found him in 1861, 1871 1891 & 1901 for Lambton County & Middlesex Counties. I have his death registration information - 1904. His parents, however, are not mentioned. Where would I go to find that information. He was Mennonite & his parents are listed as being born in Ontario.

His marriage registration - they usually list the names of parents. Obituary - it usually lists the names of family, perhaps even siblings that you can trace and see if their records mention the names of their parents. There are many resources besides census and death registrations that can be used to find this information.

The 1871 census lists an area called Cardwell, what is the present day name of this area?

Cardwell was an electoral and enumeration district that existed briefly in the late 1800's. The townships that formed this area are now part of Dufferin County, Simcoe County, and Peel County. See Cardwell District for more information.