Although Clemens may have first spoken to a large audience in 1864, according to Albert Bigelow Paine's Mark Twain: A Biography (Chapter XX) Samuel Clemens gave his first after dinner speech while living in Keokuk, Iowa. 

 

Here is the quote from the book:

"The Keokuk episode in Mark Twain's life was neither very long nor very actively important. It extended over a period of less than two years- two vital years, no doubt, if all the bearings could be known-but they were not years of startling occurrence.

Yet he made at least one beginning there: at a printers' banquet he delivered his first after-dinner speech; a hilarious speech-its humor of a primitive kind. Whatever its shortcomings, it delighted his audience, and raised him many points in the public regard. He had entered a field of entertainment in which he would one day have no rival. They impressed him into a debating society after that, and there was generally a stir of attention when Sam Clemens was about to take the floor."

We are very excited to have the play "The Report of My Death" coming to Keokuk next week. I hope lots of people on the Mark Twain forum who live in the Midwest will come to see it. We are only 2 ½ hours from St. Louis and only 1 hour from Hannibal!