Yellow River State Forest Trail is a standout hiking destination in Harpers Ferry, IA, covering 9.0 miles with 1000ft of elevation change. Stats: 9.0 miles, 1000ft gain, Hard. Type: Loop. Surface: Rocky. Time: 5 hours. Fee: Free. Dogs: Yes, on leash. Permit: No. Wildlife: deer, bears, turkeys. Best seasons: Scenic ridgelines in northeast Iowa. Pack water, layers, and appropriate footwear. Conditions vary across IA. Leave No Trace: stay on trail, pack out all waste, respect wildlife.