Kokee State Park, Mountains, Kalalau Valley, Waimea Canyon
Kokee State Park, Kauai.
Make sure you take along plenty of snacks, water and sunscreen and a camera. There is a concession in the state park, but pretty limited in what they offer. Also, the elevation gets up over 4000 feet (nearly 1500 meters) so bring a sweater too.
From Kaumualii highway in Waimea, turn mauka (toward the mountains) onto Waimea Canyon Drive. Feel free to stop anywhere along the way to take in the sights, but keep in mind that the locals go up and down these mountains daily and you should pull over when someone gets up behind you. Just pull over and wave, the folks appreciate it.

Like I said, don't be shy to pull over and take a look wherever you feel like it - You'll miss a lot if you don't get in just a bit less of a hurry.
This is an informal pullout with waterfall view (Waipo'o Falls - discussed next) .75 m past the 12 mile marker on HWY 550. It's right across the street from a cluster of picnic pavilions and a comfort station.
Right around the 3000 foot level (elevations are marked along the way) and just past the 12 mile marker is a green railing. Stop and take a look. When I was a child, this waterfall was hugely active year-round. Nowadays, because of the water being pulled off for agriculture, the flow has slowed substantially. Nevertheless, it is still quite an impressive fall at nearly 3000 feet above sea level.
No matter what the weather, Kokee Natural History Museum is open every day of the year from 10 am to 4 pm to greet and assist park visitors. That includes all holidays.
Admission is free, though there is a donation box at the door. A suggested donation of at least $1 per person is suggested; the Museum receives no State funding for operations. There is an accessibility ramp into the Museum. Children are welcomed.
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