Islands, by their very isolated nature, seem to inspire curiosity: How big is it? How long is that beach? Who lives there? Like the water around them, interest encircles them, perhaps because, unlike many continent-affixed places, their borders are definite, affording a genuine escape. These American isles represent some of the intriguingly superlative, quirky and wild within the nation’s fresh and sea waters.

The Nation’s Largest Island: Hawaii

Fittingly known as the Big Island, Hawaii encompasses over 4,000 square miles, almost twice the size of the other Hawaiian Islands combined. It claims both the southernmost point in the United States, Ka Lae, also known as South Point, and the tallest mountain, Mauna Kea, more than 33,000 feet if measured from the ocean floor but only 13,796 feet above sea level.

Most Harmonic Island: Stockton Island, Wisconsin

The undeveloped Stockton Island in the Apostle Islands National Lakeshore in Lake Superior is renowned for its “singing sands” on Julian Bay Beach that resound in squeaks and audible riffs when walked on or rubbed.

Most Accommodating Islands: Manhattan, New York City

There are 92,000 hotel rooms concentrated largely on Manhattan Island, though the borough is officially made up of eight islands: Manhattan Island, Ellis Island, Governors Island, Liberty Island, the conjoined Randalls and Wards Islands, Mill Rock, Roosevelt Island and U Thant Island.

More Eagles Than Bears, More Bears Than People: Admiralty Island, Alaska

The National Park Service estimates 2,500 bald eagles live on Admiralty Island, located between Juneau and Sitka in southeast Alaska. The island also supports about 1,000 brown bears, or roughly one per square mile, and just under two for each human resident (the human population is 572).

Only Lefty Island: The U.S. Virgin Islands

A Caribbean territory of the United States, the U.S. Virgin Islands is the only place in the country where cars travel on the left side of the road, a throwback to European governance.

Predator/Prey Microcosm: Isle Royale National Park, Michigan Since 1958, researchers have been studying the relationship between wolves and moose on remote Isle Royale in Lake Superior, one of the least-visited national parks in the contiguous United States. At this winter’s count, the population of wolves was down to two and moose up to 1,300.

The Most Unusual Seasonal Employees: Mackinac Island, Michigan More than 500 horses are ferried at the start of the summer season onto Mackinac Island in Lake Huron where it meets Lake Michigan. Cars have been banned from the 3.8-square-mile

Victorian vacation destination since 1898, and horses sub for engines, pulling everything from private carriages to garbage wagons.

The Longest Stretch of Undeveloped Barrier Island: Padre Island, Texas

Between the Gulf of Mexico and Laguna Madre in South Texas, Padre Island National Seashore protects 70 miles of coastline, dunes, prairies and wind tidal flats. It attracts nesting Kemp’s ridley sea turtles and 380 bird species.

The First Water Trail: Maine Island Trail

According to the Maine Island Trail Association, its 375-mile recreational waterway along the coast of Maine is the oldest water trail in the country. Along it, over 200 island and mainland sites, two-thirds of them private, are open for visits or camping reached via kayaks, sailboats or powerboats.

The Nation’s Largest Coral Barrier Reef: Florida Reef Tract Within the Florida Keys National Marine Sanctuary lies the world’s third-largest barrier reef ecosystem, running nearly 150 miles from Soldier Key in Biscayne Bay to the Dry Tortugas. The sanctuary, which surrounds the Florida Keys archipelago, protects most of the reef as well as over 6,000 species of marine life and countless coral and mangrove islands.

Smallest Ferry-Served Island in Washington’s San Juans: Shaw Island Though the Benedictine nuns of Our Lady of the Rock no longer operate the ferry landing at Shaw Island, they continue to run a farm there and sell some of their products, including cheese and herbs, at the Shaw General Store. The store is the only commercial enterprise on the 7.7-square-mile island apart from 11 campsites run by the Shaw County Park.

Treasury of Conchs, Whelks and Scotch Bonnets: Portsmouth Island, North Carolina

Thanks to a south-facing beach, gradually sloping sea floor and relatively small waves, hundreds of shells wash up daily, many of them undamaged, on Portsmouth Island, south of Okracoke Island in the southern Outer Banks barrier islands. Look for the state shell, the Scotch bonnet, along with lightning whelks, helmet conchs and sand dollars.

Largest Gray Seal Haul-Out on the Eastern Seaboard: Monomoy Island, Massachusetts

Largely protected by the Monomoy National Wildlife Refuge, the barrier island south of Cape Cod attracts up to 7,000 gray seals year round. Harbor seals join them in the summer.

Best Shade Tree: John’s Island, South Carolina

The 65-foot live oak known as the Angel Oak Tree in Angel Oak Park on John’s Island, just outside Charleston, produces 17,200 square feet of shade on a sunny day. When it was registered with the Live Oak Society in 1934, it had a girth of 22 feet. Today some of its branches are so massive they rest on the ground.