U
- (Sitka City and Borough) Unishka Island
- (Prince of Wales-Hyder Census Area) Unlucky Island
- (Sitka City and Borough) Urilof Island
- (Lake and Peninsula Borough) Ugaiushak Island
- (Kodiak Island Borough) Ugak Island
- (Kodiak Island Borough) Ugak Island
- (Kodiak Island Borough) Uganik Island
- (Campbell County) Ugamak Island
- (Aleutians West Census Area) Ugidak Island
- (Bethel Census Area) Ukak
- (Bethel Census Area) Uknavik
- (Campbell County) Ukolnoi Rocks
- (Campbell County) Unimak Island
- (Lake and Peninsula Borough) Unavikshak Island
- (Aleutians West Census Area) Unalga Island
- (Campbell County) Unalga Island
- (Aleutians West Census Area) Unalaska Island
- (Aleutians West Census Area) Umnak Island
- (Campbell County) Umla Island
- (Campbell County) Umga Island
- (Aleutians West Census Area) Umak Island
- (Aleutians West Census Area) Uliaga Island
- (Nome Census Area) Ukivok
- (Aleutians West Census Area) Ulak Island
- (Aleutians West Census Area) Ulak Island
- (Campbell County) Ukolnoi Island
- (Lake and Peninsula Borough) Ugashik
- (Nome Census Area) Unalakleet
- (Aleutians West Census Area) Unalaska