Barnum is nearly two-thirds of the way through his journey to paddle down the entire Ohio River.
He left Pittsburgh on Aug. 12, and had covered about 600 miles in the 26 days prior to his arrival in Louisville on Saturday evening.
Barnum is doing it to promote of all things a form of an online currency called Dogecoin that has made possible more than $100,000 in donations to charity.
He said the last month has been a long, strange trip.
"We meet a lot of cool people all the time," he told WAVE 3 News over the weekend. "The Ohio River is home to some interesting animals, too. We had some raccoons attack the other night, and eat all of the peanuts we had at camp while I was writing a blog entry, so it was a cool experience."
Barnum has another 367 miles to go to reach the end of the Ohio River in Paducah, but he said he might just keep paddling down the Mississippi River and beyond.
You can follow Barnum on his journey at his blog: http://ibelieveindoge.tumblr.com/
Copyright 2014 WAVE 3 News. All rights reserved.