Law Enforcement Agencies in Pine Knoll, MN MN › Aitkin County Agencies serving the city of Pine Knoll in MN. Agency Types in Pine Knoll County Jails 1 agencies Municipal Police 1 agencies Sheriff 1 agencies All Agencies in Pine Knoll, MN Aitkin County Jail Aitkin County Aitkin County Sheriffs Office Aitkin County Aitkin Police Department Aitkin County