Nothing on the Web site.
Robert writes in:
Located next to Smoky Mountain Travel Mart: mail drop located on wall. Also in parking garage across street from terminal level one.
The Terminal Maps the airport provides aren’t good at all. Fortunately it looks like the Travel Mart is nearly impossible to miss on your way to security. I wasn’t able to locate the one in the parking garage from Google Maps (sometimes they are curbside so I had to check).
Last updated 19 August 2018