Stevens Thomson Mason (October 27, 1811 – January 4, 1843), also known as Stevens T. Mason, Tom Mason, The Boy Governor, and lesser known nicknames Young Hotspur and The Stripling, was the territorial governor of the Michigan Territory, and later the first Governor of the state of Michigan. Mason guided the Michigan Territory into statehood. He was first appointed acting Territorial Secretary at the age of 19, then became acting Territorial Governor in 1834 at the age of 22. He was elected governor of the state of Michigan at age 23 as a member of the Democratic Party in 1835, and served until 1840. Mason is the youngest state governor in American history.