The crossword solution for the term 'Neighbor of Kentucky' is Ohio, which is a four letter word. Ohio is a state located in the Midwestern United States and is bordered by Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the south, and Indiana to the west. It is the 34th largest state in the United States and the 7th most populous. Ohio is the only state to have a border on both the Ohio River and the Mississippi River. It is also known as the 'Buckeye State' due to its abundance of Buckeye trees. Ohio is the neighbor of Kentucky, making it the answer to the crossword puzzle.