Jonas Pach was a son of Mozes Pach and Mietje Groen. He married in Amsterdam on 6 February 1895 to Klara Reimer. They had 3 children together: Mietje, Mozes and David. After the death of Klara Reimer on 28 January 1919, he remarried Rebecca Vogel on 10 December 1919 in Amsterdam Togehter they had another two children: Joel and Abraham.
City archive of Amsterdam, archive card of Jonas Pach.