Willem Pieters Geldersma, born circa 1778, died in Franeker on February 2, 1840, aged approximately 62 years.

Willem was married to
Aafke Pieters Vlietstra, born circa 1789 (?).

• 1 : Trijntje Willems Geldersma, born in Franeker on September 5, 1812, died in Harlingen on January 25, 1902, aged 89 years.
  Trijntje was married in Franeker on May 14, 1837, at the age of 24 to Ernst Jans Koster (aged 20 years), born in Franeker on August 1, 1816, son of Jan Bernardus Koster and Klaske Jans Groeneveld, died in Harlingen on April 10, 1862, aged 45 years.