It was Bald Bluff Mountain in Amherst. Just like the sign says. Possibly over 50 miles from Mt Katahdin.

UPDATE: Gentle Viewer Mark Ward correctly identfied the Mystery Mountain as PASSADUMKEAG Mountain which was confirmed through Google and MSN Maps despite what I and that sign says. So I've misidentified it TWICE! I am soooooooooooooooo lucky I didn't go on TV. Although more people have seen it on here now than on that little news clip. :)