From 77 take 271 north, get off at 303 and turn right. Take 303 down to the first light which is riverview. Turn left on river view. Take riverview to boston mills rd and turn left. (if you pass the ski resort you have gone to far by 500 ft.). Follow Boston Mills up ( its a very curvy road) to blue hen falls its about a mile up the hill on your right.
Be careful it can be very slippery I know for a fact. This is a good waterfall in all seasons. It freezes in winter for a really nice effect. If you follow the river down you will see many little cascading water falls and you will reach a larger one that looks like a water slide. Its a very beautiful park and there are two different trials to choose from.