Ipe Oosterhof was born on 14 January 1842 in Grootegast, Groningen, the Netherlands. His parents were Roelf Ipes Oosterhof (1814) and Aaltje Hendriks Melissen, who had married on 21 December 1840. Ipe married Klaasina de Vries (1847-1935). He was employed as a farmhand/laborer.
Ipe Oosterhof had the following siblings:
- Hendrik Oosterhof (born 14 February 1844)
- Klaas Oosterhof (born 10 January 1850)
- Albert Oosterhof (born 9 April 1853)
- Klaaske Oosterhof (born 24 August 1856)
- Klaas Oosterhof (born 1 September 1863)