Idaho is another state with a history of very strong gold production over the years. Hopefully, by now it is beginning to get warm enough to do a little gold mining in Idaho. One of the problems of prospecting in Idaho is that there is not always enough water, and a good gold detector is probably a good investment if you are really serious about gold prospecting in Idaho.
This is document about gold mining along the Snake River. It is full of interesting information and it is definitely worth looking at if you are even thinking prospecting in Idaho.