Tennessee whiskey is a type of Bourbon whiskey made in Tennessee. Legally, both NAFTA and Canadian law treat Tennessee whiskey as Bourbon, but both note that it comes from Tennessee. There are currently four brands of Tennessee whiskey on the market: Jack Daniel's, George Dickel, Collier & McKeel, and Pritchard's.
Some Tennessee whiskies go through what is called the Lincoln County Process, where the whiskey is filtered through many feet of hardwood (usually maple) charcoal. Jack Daniel's, George Dickel, and Collier & McKeel undergo this step, with adds a charred flavor to the whiskey, but reduces impurities and smooths the spirit. Pritchard's does not.