Just past the 4-mile marker past Hanalei, you'll likely see cars parked along the side of the road. These belong to folks who have decided to take the short hike 150 feet down to one of Kauai's most beautiful beaches, Lumaha'i Beach. The path down to the beach is not easy to find and the walk down can be a bit slippery.
This is the end of the mile-long beach that I prefer, but if you can't find a place to park you can drive down the hill and park in the parking area under the ironwood trees that is located right before the bridge over the Lumaha'i River.
Don't even think about swimming at this beach. The surf is dangerous especially in winter and strong currents and undertow are present year-round. The eastern end of the beach, (reached via the path from the cliff) is the most stunning especially when waves are crashing against the rocks that extend from the far eastern point of the beach.
This beach was made famous in the motion picture South Pacific and bears the nickname of "nurses' beach" since this is where Ensign Nellie Forbush played by Mitzi Gaynor "wash(ed) that man right our of my hair."