Currently, there no U.S. states that start with any of the following letters: B, E, J, Q, X, Y, and Z. So your challenge is to get some states that start with those letters.
British Columbia, if the U.S. somehow gains control of it during the 54-40-or-fight years.
Erie, if the area encompassed by Connecticut's Western Reserve in Northern Ohio/NW Pennsylvania became a state. It's plausible considering that the state of Michigan was named after Lake Michigan, and the province of Ontario was named after Lake Ontario.
Jefferson, if the 1941 northern California/southern Oregon attempt at secession was successful.
Queensland, if the U.S. beats Australia to the name. Queensland is a plausible name for the colony of Virginia (which in OTL was named after Queen Elizabeth I, the Virgin Queen).
Xeria, based on the Greek word for dry,
xeros. A good name for one of the Desert Southwest states.
Yavapai, for the Native tribe of the same name. Possibly an alternate name for Arizona (where Yavapai county can be found). While I'm at it, Yuma would also be a plausible name.
Zephyria, a plausible name for a west-coast state (Zephyr was the ancient Greek god of the west wind).
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