Answer: Smokey Bear

There are lots of hard-working public service announcement mascots out there such as Woodsy Owl, McGruff the Crime Dog, and Eddie Eagle just to name a few. None of those mascots are so popular as to merit having their own specialized mail-delivery zip code, however, except for Smokey “Only You Can Prevent Wildfires” Bear (the slogan was updated in April 2001).

What boosted Smokey to the kind of fame that brings in truckloads of fan mail was the decision of the U.S Forest Service to adopt an actual bear to serve as the mascot. In 1950, firefighting crews rescued an American black bear cub from a massive wildfire in the Capitan Mountains of New Mexico and the Forest Service adopted it as a living embodiment of Smokey Bear. The bear cub proved to be so popular with children across the country that the Forest Service started receiving piles of fan mail. So much fan mail, in fact, that by 1964, the U.S. Postal Service assigned Smokey his own mailing zip code to make sorting the bags of fan mail easier. That zip code, for the curious, is 20252 (which is still in use).

Smokey the Bear went on to live at the National Zoo for the remaining 26 years of his life and, after dying of old age, was buried in Smokey Bear Historical Park in Capitan, New Mexico. The Smokey Bear character remains the most popular public service announcement mascot in U.S. history and licensing of his image brings in millions of dollars every year to help fund fire prevention education efforts.