Jackass Hill, CA…Mark Twain made an appearance at Jackass Hill to let folks know that even ole Twain be wearin his mask. Mark Twain made the PSA video for the Calaveras Visitors Bureau and Film Commission. Tuolumne County may need to get a bit of the credit as while “The Celebrated Jumping Frogs” was all about Calaveras. Jackass Hill happens to be south of the river.