The Engelmann-Hilgard family circle includes members of the Engelmann and Hilgard families who migrated to the United States beginning in the 1830s and their relatives who remained behind in the German states. The two families both originated from the Kurpfalz region. Three collections are associated with these families: the Engelmann Family Letters, the Hilgard Letters, and the Henry Villard Family Letters. The Hilgard family circle includes people who appear in three sets of correspondence: (1) between the Engelmann siblings to their sister Margarethe Hilgard, née Engelmann (2) between Henry Villard alias Heinrich Hilgard, who immigrated to the USA, and his relatives in Germany (3) between Theodor Hilgard and his mother Maria Dorothea Hilgard, née Engelmann