Missouri farmers stand to benefit under a free-trade pact currently before Congress.
He said Missouri exports large amounts of pork and soybeans, products that have a ready market in South Korea.
"So it makes sense for us to be here in St. Louis because a good deal of those crops basically find their way to St. Louis and past St. Louis on the great Mississippi," Vilsack said.
Vilsack said the agreement would eliminate 60 percent of the current tariffs South Korea levies on U.S. agriculture products.
He also noted that Missouri has the most farms of any state in the country, with 108,000.