I was adopted by Wilbur Cora Hjertstedt when I was almost 6. I know almost nothing of the Hjertstedt heritage except I visited their town of origin in Grenna, Sweden on Lake Vettern. There are several Hjertstedts in the cemetery there and some cousins still living there. I have heard that my grandparents came to America and were married on board the ship at the ages of 17 and ??
My cousin Howard Hjertstedt and his wife Grace live in Sheffield,IL. She has been a teacher and maybe has more info.
Good luck.
Leanne