Here's a single book by the Dean of Treasure Hunting, Thomas Penfield, covering the lost and buried treasures in FOUR states. Each state is covered separately, and broken down county by county. In addition, each state also has a Metal Detector Sites section also broken down by counties. A must have book for treasure hunters in the midwest.
"This book is a good starting point for anyone wanting to search the varied leads of Kansas, Nebraska and the Dakotas." The northern High Plains States offer vast treasure potentials.