Yes, with conditions
1. What the city publishes
1- The use of metal detectors as a recreational tool is permitted in parks. 2- The use of metal detectors is explicitly prohibited at Rose Hill Cemetery, White Oak Cemetery, Griffy Lake Nature Preserve, Leonard Springs Nature Park, Latimer Woods, and Switchyard Park. 3- Magnet fishing is prohibited without permission. 4- If any person using a metal detector locates an item of archaeological or historical significance, that person must notify the Parks and Recreation Department of the find.
Source: bloomington.in.gov/parks/parks
2. The state rule also applies
Written permission from the Department of Natural Resources, and only on DNR property.
3. County rules
Awaiting review.