Technically, Jack Daniels is a Tennessee Whiskey. It's made in Lynchburg, TN and must be distilled from at least 51% corn. Most bourbons are made in Kentucky, and must be distilled from at least 51% corn and aged in charred new oak barrels. So Jack Daniels is technically a bourbon, but it doesn't meet all the requirements to be called a bourbon. That's why it's called a Tennessee Whiskey.