Great quiz! I think you're missing the Confederacy, and if you include occupations, Dominican Republic, Haiti, Honduras, and Costa Rica. The Confederacy bordered the Union while it lasted (1861 - 1865). Since the United States occupied both the Dominican Republic and Haiti, but at different times, the United States bordered the Dominican Republic in 1915, 1925 - 1934, and 1994 - 1995. The United States bordered Haiti in 1965 - 1966. As for Costa Rica / Honduras, the United States occupied Nicaragua from 1912 to 1933. (Source)
I need to make up my mind about leased territory and invasions. I told myself I’d think about Dollyfroggy’s comment when I first saw it and two years later I’ve still done nothing about it.
this quiz also includes leased lands hmm, but not guantanamao