The Waianae Mountains are a mountain range located on the island of Oahu in Hawaii. Stretching approximately 30 miles, they are known for their rugged terrain and scenic views. The highest peak, Ka'ala, rises to about 4,000 feet, making it the tallest point on the island. The mountains are primarily composed of volcanic rock and are home to diverse flora and fauna. These mountains play a significant role in the local ecosystem and climate. They create a rain shadow effect, leading to drier conditions on the leeward side, where the town of Waianae is situated. The area is popular for hiking, with trails that offer breathtaking vistas and opportunities to explore the unique natural environment.