Long Island is 149th on the list of the world's largest islands. Until 1899 it was the largest in the USA; then the USA acquired Puerto Rico, Guam and the Philippines, as part of the settlement that ended the Spanish–American War.
The Philippines gained independence in 1946, but both Puerto Rico and Guam are still "organized, unincorporated territories" of the United States. The main island of the Puerto Rico archipelago (itself known as Puerto Rico) is the smallest of the Greater Antilles, and the 82nd largest island in the world; today, it's the third largest island in the United States.
The largest of all is Hawaii – the 75th largest island in the world (also known as 'the Big Island', to distinguish it from the group and state to which it gives its name). And the second largest island in the modern USA is Alaska's Kodiak Island. Hawaii, Puerto Rico and Long Island are the only three of the USA's ten largest islands that are not in Alaska.
After Long Island, the largest island in the 48 contiguous US states is Padre Island – a barrier island in Texas. (A barrier island is one that lies parallel to a mainland coast, having been formed from sand by wave and tidal action.) Padre Island is the USA's 31st largest island. Thirty–second on the list is Guam, and thirty–third is Isle Royale – in the northwest of Lake Superior, belonging to the state of Michigan.
Thirty–seven of the USA's fifty largest islands are in Alaska. Of the other thirteen, six are in Hawaii, five are in the other 48 states, and two (as we've seen) are in unincorporated territories.
The fourth and fifth largest islands in the 48 contiguous states are Whidbey Island (in Puget Sound, belonging to Washington state) and Drummond Island (part of Michigan, and the third largest island in Lake Huron – the two largest being in Canada). Whidbey and Drummond are respectively 40th and 47th on the USA's list.
© Haydn Thompson 2021