To find treasure or historical artifacts in Wisconsin, start by scouring old county maps for roads no longer used or ghost towns. State parks and national parks are off limits for treasure hunting in Wisconsin and prohibit the use of metal detectors for treasure hunting. Private land is the best bet. In 2009 a man in England found a huge Saxon treasure on private land. He had permission and split the treasure with the owner. If you intend to investigate on private land, always secure permission.
The town of Donaldson has long disappeared and lies in Vilas County off of Highway B near the Michigan border and the Wisconsin town of Land O' Lakes. The small town was once a former logging town and was abandoned during the 1920s. The remains are situated near abandoned railroad tracks and some of the foundations still stand but all the buildings are gone. According to the Land O' Lakes Chamber of Commerce, the area is not a historic site but it is mostly private land and you need to seek permission before treasure hunting.(ref3)
The town of Hurley in Iron County still exists, but only 2,000 people inhabit the town that once ballooned to more than 7,000 people. The town lies in the northern part of the state off Highway 77. The town still has 30 bars and for a small town that seems like a lot, but it is a reflection of the town's tawdry past. According to the Iron County Historical Museum, Hurley catered to miners and loggers in the late 1800s and then during prohibition catered to gamblers and drinkers. At one time the town had more than 80 saloons run by Chicago gangs during prohibition. Many of the old saloons are gone and lie on abandoned property on private land. Not much of the buildings remain. Special permission is needed to treasure hunt.
Star Lake lies 8 miles north of the Vilas County Museum in Saynor, Wisconsin. The town started due to intense logging in the area and at one time had a population of 600 people, according to the Vilas County Historical Museum. The remains at the site include a post office, grocery store and some homes. When the area was logged out, the logging company moved to a site in western Wisconsin. The land now is privately owned by William Hense, according to the museum. Seek permission before exploring the area; the store is closed during the winter.