Largest Islands in the United States

While many travelers think only of tropical destinations like Hawaii or the Caribbean, the vast majority of America’s massive insular territory lies across the rugged, glaciated coastlines of the Pacific Northwest. From the volcanic peaks of the Hawaiian archipelago to the sprawling wilderness of Alaska’s Alexander Archipelago, this comprehensive guide ranks the top 25 largest U.S. islands by square mileage and acreage, highlighting unique geographic trends, population hubs, and remote coastal ecosystems across North America.

Rank	Island Name	State / Territory	Land Area (sq mi)	Land Area (Acres)
1	Hawaiʻi (The Big Island)	Hawaii	4,028	2,577,920
2	Kodiak Island	Alaska	3,588	2,296,320
3	Puerto Rico	Puerto Rico	3,513	2,248,320
4	Prince of Wales Island	Alaska	2,577	1,649,280
5	Chichagof Island	Alaska	2,080	1,331,200
6	St. Lawrence Island	Alaska	1,983	1,269,120
7	Admiralty Island	Alaska	1,684	1,077,760
8	Nunivak Island	Alaska	1,625	1,040,000
9	Unimak Island	Alaska	1,590	1,017,600
10	Baranof Island	Alaska	1,570	1,004,800
11	Long Island	New York	1,401	896,640
12	Revillagigedo Island	Alaska	1,145	732,800
13	Kupreanof Island	Alaska	1,086	695,040
14	Unalaska Island	Alaska	1,051	672,640
15	Nelson Island	Alaska	843	539,520
16	Kuiu Island	Alaska	758	485,120
17	Maui	Hawaii	727	465,280
18	Afognak Island	Alaska	698	446,720
19	Umnak Island	Alaska	692	442,880
20	Oʻahu	Hawaii	597	382,080
21	Kauai	Hawaii	552	353,280
22	Atka Island	Alaska	405	259,200
23	Attu Island	Alaska	344	220,160
24	Etolin Island	Alaska	336	215,040
25	Montague Island	Alaska	313	200,320

Alaska’s Sheer Dominance: Alaska utterly commands the list, claiming 19 of the top 25 positions. The state’s vast archipelagos mean it boasts more total islands than the rest of the country combined.
The High-Density Exceptions: While most of the top entries are remote, sparsely populated, or protected wilderness reserves, islands like Long Island (#11), Oʻahu (#20), and the territory of Puerto Rico (#3) double as dense, massive economic and cultural hubs home to millions of residents.
The Extreme Pacific Edge: Attu Island (#23) represents the literal end of the United States. Located at the furthest western tip of the Aleutian Chain, it is closer to the Russian coast than it is to mainland Alaska.
The Hawaiian Scale: Out of the eight main Hawaiian islands, only four make the top 25 cut: The Big Island (#1), Maui (#17), Oʻahu (#20), and Kauai (#21). The remaining islands, like Molokai and Lanai, fall significantly below the 300-square-mile threshold.