There is a book called Darkhouse Spearfishing Across North America by Jay Leitch. In it he speared and/or reported on all the states that allow darkhouse spearfishing (except North Dakota). Off the top of my head I think they were, Alaska, Montana, Minnesota, South Dakota, Michigan, Wisconsin. The author did not spear in N.D. as he was a Minnesota resident, and you can't spear in N.D. if your state of residency does not allow non-residents to spear.