This 10 mile hike has about 700 feet of elevation change and will be led at a pace of about 2.25-2.5 mph. We will begin on the scenic Switchback Trail in the McKeldin area of Patapsco Valley State Park. We'll cross the North Branch Patapsco River from Carroll County into Baltimore County and complete a big loop through woods, past a water-filled quarry, and along river shoreline. After re-crossing the North Branch at a different spot, we will finish up…