The term 'Neighbor of Wyoming' can be answered by two crossword solutions: IDAHO (5 letters) and Utah (4 letters). IDAHO is a state located in the northwestern region of the United States, bordered by Montana to the east and Washington and Oregon to the west. It is also bordered by Wyoming to the south and Canada to the north. Utah is a state located in the western United States, bordered by Colorado to the east, Wyoming to the northeast, IDAHO to the north, Arizona to the south, and Nevada to the west. Both IDAHO and Utah are neighbors of Wyoming.