Oscar Heiden was born in either 1868 or 69 and was the child of Christoph Ludwig Friedrich Heiden was born on March 19, 1825 to Johann Jochim Diederich Heiden and his wife, the former Ilsabe Catharina Sophia Teschenow and was a younger brother of Maria Heiden and, therefore, uncle to August Heiden and his half-sister, Fredericka (Heiden) Schmidt.

On January 27, 1883, Ludwig sent a letter to his nephew, August Heiden in America containing this information. Oscar would have been August's first cousin.