When Isaac Oberholtzer was born on 24 May 1838, in Waterloo, Waterloo, Ontario, Canada, his father, Jacob Moyer Oberholtzer, was 38 and his mother, Hannah Erb, was 25. He married Mary Ann Wismer on 30 September 1863, in Waterloo, Waterloo, Ontario, Canada. They were the parents of at least 3 sons and 3 daughters. He lived in Howick, Huron, Ontario, Canada in 1871 and Kitchener, Waterloo, Ontario, Canada in 1911. He died on 24 February 1887, in Berlin, Waterloo, Ontario, Canada, at the age of 48, and was buried in Berlin, Waterloo, Ontario, Canada.