Asia and
Oceania: It's been proposed OTL that a state be formed out of US possessions in the Pacific; for example, the Governor of Guam fairly recently
mulled over reunifying with the Northern Marianas and petitioning to be admitted as the 51st state. A state that incorporated all territories the US had OTL (such as those two, American Samoa, Palau, etc.) could count for both continents, or could be admitted as two states. (Alternatively, they could be admitted as part of "Greater Hawaii," also proposed OTL.)
South America: In 1938, Édouard Daladier
proposed transferring French possessions in the Caribbean and Pacific, possibly including French Guiana, to the United States in return for the unlimited right to buy US aircraft on credit. While this would be problematic to get through the French parliament, it would leave the US with a potentially state-sized territory in South America if it went through.
Alternatively, the other Guyana has a
sizable statehood movement, and allegedly a third of Guyanese people live in the US. This could be acted upon by a sufficiently expansion-minded US leadership.
Europe: Sicily had a somewhat significant statehood movement immediately following WWII; it probably wouldn't have amounted to much on its own but could have been helped along by a sufficiently terrible situation on the mainland that wouldn't require the US to instead prop up a fictional "Sicilian government of Italy." Maybe the US negotiates a more limited peace with Fascist Italy, and leaves an intact government that is seen as legitimate but no friend of the US or the USSR.
Africa: A Liberia that never formally declares independence could fit this model, especially if Liberia becomes surrounded by post-colonial states that end up being hostile to the Americo-Liberian upper class. A petition for statehood could guarantee a degree of security, and could concievably be accepted by Congress if Liberia was significant enough.