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didn't the Oregon trail go through NE ? Look for places that the trail went across creeks or rivers. Look for campsites. Here is a hint: I've read that the mules didn't like to pull in a cold collar. This means they crossed the creek at the end of the day not first thing in the morning. Research is the key. Read, read,read. Check out old posts here, there is a wealth of information
Southern Nebraska hunter here (1/2 mile from Kansas) and I have not found anything really good yet other than a Black Hills silver ring. I been hunting parts of Kansas and I find more cool stuff there.