Thornleigh to Hornsby is a 10.2km, grade 4 One way hike located in Berowra Valley National Park New South Wales. The hike should take approximately 4 hrs to complete.
Starting at Thornleigh station you walk through suburban streets for a short while before diving into the bush at the southern end of Berowra Valley Regional Park. Soon after visiting the site of the historic Zig Zag railway you start wandering through the Berowra Creek valley passing a few cascading creeks. The track undulates along the side of the valley visiting a range of environments from moist fern forest to the drier grass tree and eucalypt forests of the ridge. There is a short side trip to visit the Westleigh engravings and a chance to pop down to fishponds before climbing up the depression era stone steps to Hornsby station.