A small waterfall at Hacklebarney State Park. The 978 acres Hacklebarney State Park is a popular year round destination for New Jersey hiking. The Black River flows through the middle of the park and massive boulder rocks are struin through out the park. These boulder rocks create many beautiful waterfalls and cascades that can be observed along the many trails. Hacklebarney State Park is located between Long Valley and Chester in Morris County, New Jersey.