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The United States boasts an incredibly diverse collection of islands spanning from the Atlantic to the Pacific, from tropical paradises to rugged northern territories. These islands represent a fascinating aspect of American geography that often goes underappreciated. From volcanic formations to historical landmarks, each island tells a unique story about the nation’s geological history, cultural heritage, and territorial expansion. Here are eighteen remarkable facts about America’s island treasures that showcase their diversity and significance.
Pacific Island Territories
Hawaii Is America’s Only Island State
Hawaii holds the distinction of being the only U.S. state composed entirely of islands. The Hawaiian archipelago consists of 137 islands spanning 1,500 miles across the Pacific Ocean, though only eight major islands are inhabited. The state officially joined the union in 1959, making it the 50th state. The islands formed over millions of years through volcanic activity from a hotspot beneath the Pacific Plate, creating a chain of volcanic mountains that rise dramatically from the ocean floor.
The Aleutian Islands Bridge Two Continents
The Aleutian Islands stretch over 1,200 miles from Alaska toward Russia, creating a natural bridge between North America and Asia. This volcanic island chain contains more than 300 islands, with some positioned so far west that they technically cross into the Eastern Hemisphere. During World War II, these remote islands became strategically important when Japanese forces occupied Attu and Kiska, making them the only U.S. soil occupied by enemy forces during the war.
Guam Serves as America’s Westernmost Territory
Guam, located in the western Pacific Ocean, stands as the United States’ westernmost territory and largest island in Micronesia. Spanning 210 square miles, this unincorporated territory has been under American control since 1898. The island serves as a critical strategic military location and is home to approximately 170,000 residents, including a significant U.S. military presence.
Atlantic and Gulf Coast Islands
The Florida Keys Extend Into Tropical Waters
The Florida Keys comprise an archipelago of approximately 1,700 islands stretching 120 miles off Florida’s southern coast. Connected by the famous Overseas Highway, which includes 42 bridges, these islands represent the exposed portions of an ancient coral reef. Key West, the southernmost point in the continental United States, sits just 90 miles from Cuba, making it closer to Havana than to Miami.
Manhattan Was Purchased for Remarkably Little
According to historical accounts, Manhattan Island was purchased from Native Americans in 1626 for goods worth approximately 60 guilders, often cited as $24. While this figure has been disputed and adjusted for inflation numerous times, the transaction remains one of the most famous real estate deals in history. Today, Manhattan’s land value exceeds $1 trillion, making this 22.8-square-mile island one of the world’s most valuable pieces of real estate.
Barrier Islands Protect the Eastern Seaboard
The Atlantic coast features extensive barrier island systems that shield the mainland from storms and erosion. These narrow islands, formed by wave and tidal action, constantly shift and change shape. Notable examples include North Carolina’s Outer Banks, which stretch over 200 miles and include famous locations like Cape Hatteras, and Georgia’s Sea Islands, which preserve unique Gullah-Geechee culture.
Historical and Cultural Significance
Ellis Island Processed Millions of Immigrants
Located in New York Harbor, Ellis Island served as the nation’s busiest immigrant inspection station from 1892 to 1954. During its operation, approximately 12 million immigrants passed through its facilities, with roughly 40% of Americans today able to trace their ancestry to someone who arrived through Ellis Island. The island, originally 3.3 acres, was expanded through landfill to 27.5 acres.
Alcatraz Housed America’s Most Notorious Criminals
Alcatraz Island in San Francisco Bay operated as a maximum-security federal prison from 1934 to 1963, housing some of America’s most dangerous criminals including Al Capone and Robert Stroud. The 22-acre island’s isolation and the bay’s cold, swift currents made it nearly impossible to escape, though several attempts were made. Today, over 1.5 million tourists visit the former prison annually.
Natural Wonders and Unique Features
Maui Contains the World’s Largest Dormant Volcano
Haleakalā on Maui stands as the world’s largest dormant volcano, with a massive crater spanning seven miles across and over 2,600 feet deep. The volcano rises 10,023 feet above sea level, and if measured from its base on the ocean floor, it reaches an impressive height of over 30,000 feet, making it one of Earth’s tallest mountains.
The Apostle Islands Feature Ancient Sea Caves
Located in Lake Superior off Wisconsin’s coast, the Apostle Islands consist of 21 islands known for their stunning sea caves carved by thousands of years of wave action. During winter, when the lake freezes, visitors can walk across the ice to explore magnificent ice formations within these caves. The islands’ sandstone cliffs showcase vibrant red, white, and orange colors from mineral deposits.
Puerto Rico’s Bioluminescent Bays Glow at Night
Puerto Rico, a U.S. territory in the Caribbean, hosts three of the world’s five bioluminescent bays. Mosquito Bay on Vieques Island holds the Guinness World Record for brightest bioluminescent bay, with microscopic organisms called dinoflagellates creating an ethereal blue-green glow when disturbed. This natural phenomenon creates a magical experience where the water appears to sparkle with every movement.
Territorial Expansion and Remote Islands
American Samoa Lies South of the Equator
American Samoa represents the only U.S. territory located south of the equator. This unincorporated territory in the South Pacific consists of five main islands and two coral atolls, covering approximately 76 square miles. The territory maintains strong Polynesian traditions and is home to the National Park of American Samoa, the only U.S. national park south of the equator.
The U.S. Virgin Islands Were Purchased from Denmark
The United States acquired the Virgin Islands from Denmark in 1917 for $25 million in gold, primarily for strategic military positioning during World War I. The three main islands—St. Thomas, St. John, and St. Croix—along with dozens of smaller islands, total approximately 133 square miles. Today, these Caribbean islands are popular tourist destinations known for their pristine beaches and duty-free shopping.
Dry Tortugas Hosts a Massive Coastal Fortress
Located 70 miles west of Key West, the Dry Tortugas consist of seven small islands dominated by Fort Jefferson, a massive but never-completed 19th-century fortress. This hexagonal structure contains over 16 million bricks, making it one of the largest masonry structures in the Americas. The remote location, accessible only by boat or seaplane, now serves as a national park protecting important marine habitats and historical sites.
Northern and Freshwater Islands
Mackinac Island Bans Motor Vehicles
Mackinac Island in Michigan’s Lake Huron has prohibited motor vehicles since 1898, making it one of the few places in the United States where cars are banned. Transportation occurs via horse-drawn carriage, bicycle, or foot. The 3.8-square-mile island attracts thousands of visitors annually who come to experience its Victorian-era charm and famous fudge shops.
Long Island Ranks Among America’s Most Populated Islands
Stretching 118 miles across New York, Long Island holds the distinction of being the longest and largest island in the contiguous United States. With a population exceeding 7.8 million people, it ranks as the most populated island in any U.S. state and the 17th most populous island globally. The island encompasses four counties: Kings (Brooklyn), Queens, Nassau, and Suffolk.
Volcanic Activity and Geological Marvels
Kīlauea Remains One of the World’s Most Active Volcanoes
Located on Hawaii’s Big Island, Kīlauea volcano has been erupting almost continuously since 1983, making it one of Earth’s most active volcanoes. These eruptions have added over 500 acres of new land to the island where lava flows into the ocean and solidifies. The volcano attracts volcanologists and tourists worldwide who come to witness the raw power of Earth’s geological forces.
Channel Islands Preserve Unique Ecosystems
California’s Channel Islands, located off the coast near Santa Barbara and Ventura, form an isolated archipelago that has preserved unique species found nowhere else on Earth. Often called “North America’s Galápagos,” these eight islands host over 2,000 species of plants and animals, with 145 found exclusively on the islands. The Channel Islands National Park protects five of these islands, offering visitors a glimpse of California’s natural history before human development.
Conclusion
America’s islands represent an extraordinary tapestry of natural beauty, historical significance, and cultural diversity. From the volcanic landscapes of Hawaii to the historic shores of Ellis Island, from the tropical waters surrounding Puerto Rico to the frozen expanses of the Aleutian chain, these islands demonstrate the remarkable geographical range encompassed by the United States. Whether serving as strategic military outposts, preserving unique ecosystems, or standing as monuments to American history, these islands continue to captivate visitors and researchers alike. Their stories remind us that the United States extends far beyond the continental mainland, encompassing thousands of islands that each contribute their own unique chapter to the American narrative. Understanding and appreciating these island treasures deepens our connection to the nation’s diverse geography and rich heritage.