https://en.wikipedia.org/wiki/Territories_of_the_United_StatesI think most people don't even think of these regions, all islands, as part of the United States.
I think virtually all posessions handed over to the U.S. during the 1898 Spanish-American war.
Or Islands taken back from the Japanese during World War II.
A lingering remnant of the United States' rise onto the global stage, and entry into global trade, and perhaps of a brief reach for Empire, becoming at least comparable to European imperial powers of the time, particularly imposing rule for several decades over the Phillipines.
There are about 4 million U.S. citizens who live in these places, many of them fiercely patriotic and serving at a high ratio in our military. They tend to have naval bases and a large U.S. military presence.
Some beautiful and lesser-known frontiers of the United States.
One lady I spoke to said she thinks Guam is actually more beautiful than Hawaii.