U.S. agriculture is undergoing a tidal wave of change in its structure. A shift to supply chains and away from commodities and commodity markets is the hallmark of this new wave. The new agriculture of the 21st century will bring with it a new geography that may be nothing short of a revolution for rural America. Supply chains will tend to concentrate activity geographically and change the local economic dynamic where they do locate. Finally, the tide of change in agriculture's structure means a whole new slate of policy issues. Concentration, market access, and the delivery mechanism for government support all become bigger concerns with supply chains. But perhaps the biggest policy challenge looming ahead is addressing rural America's economic challenges. A much broader approach will be needed if rural America is to unlock its economic potential in the 21st century.