1: Region and Ecoregions

Home to the majority of Hawaii's Population and a wealth of activities and attractions, Oahu is separated into 5 distinct regions which includes: 

• Honolulu
• the Windward Coast
• Central Oahu
• The leeward Coast 
• the North Shore 

World famous Waikiki is located on the south shore of Honolulu. 

Some attraction from these places are: 

Honolulu: Hawaii's  largest city that looks like any other big metropolitan center with tall buildings. In fact, some cynics refer to it as "Los Angeles West." But within Honolulu's boundaries, you'll find rain-forests, deep canyons, valleys and waterfalls, a nearly mile-high mountain range, coral reefs, and gold-sand beaches. The city proper where most of Oahu's residents live, is approximately 12 miles wide and 26 miles long, running east to west, rougly between Diamond Head and Pearl Harbor. Within the city are seven hills laced by seven streams that run to Mamala Bay. 
The Windward Coast: Kailua Beach Park, Oahu located in the Windward Coast, overlooks Bay and the Monkula Islands and is a great spot for kayaking, windsurfing and other water sports. 

Central Oahu: One of the best attractions in Central Oahu is the Five Pearl Harbor Historic Sites that honor this National Historic Landmark where World War ll both began and ended. 

The Leeward Coast: Kaena Point, Oahu is a sacred spot at the western most tip of Oahu accessible only by hike. 

The North shore: Here's the Hawaii of Hollywood- giant waves, surfers galore, tropical jungles, waterfalls, and mysterious Hawaiian temples. Also, if you're looking for a quieter  vacation, closer to nature and filled with swimming, snorkeling, diving, surfing, or just plain hanging out on some of the world's most beautiful beaches, the North Shore is the perfect spot.  

Source: Gohawaii.com/oahu/regions-neighborhoods