St. Clair actively opposed Ohio becoming a state. He hoped that Ohio would not become two states instead of one. If this happened, St. Clair believed that the Federalists would outnumber the Democratic-Republicans. The Federalists could then continue to control the government of the new states.

St. Clair then retired to his home in western Pennsylvania. There he began to make stoves and ovens. However, he constantly was loaning out money. He then ended up with financial problems and had to move into a log cabin, where he died in 1818