Near the 19-mile marker, Wailua Valley State Wayside lookout comes up on the right. The overlook provides a broad view into verdant Keʻanae Valley, which appears to be 100 shades of green. You can see a couple of waterfalls (when they’re running), and Koʻolau Gap, the break in the rim of Haleakalā crater, on a clear day. Turn towards the sea for an outstanding view of Wailua Peninsula as well – don’t miss this.
A word of caution: the sign for the wayside appears at the last moment, so be on the lookout.