Missouri is called the Show-Me State. The Missouri Secretary of State traces the slogan to Congressman Willard Vandiver at a naval banquet in Philadelphia. “…frothy eloquence neither convinces nor satisfies me. I am from Missouri. You have got to show me.”
Vandiver did not invent the phrase. It was in print by 1893, when the Omaha Daily Bee printed a letter from a man who wrote, “I am from Missouri and they must show me something.” The state gives the banquet as 1899. One researcher, Barry Popik, dates it to 1900, and the slogan has never been made official.