Editors' Summary: The devastation wrought by Hurricane Katrina brought to public attention the role of land use planning in mitigating natural disasters and which level or levels of government should decide whether and how to undertake this planning. In the Upper Mississippi River Basin, 6 federal agencies, 23 state agencies in 5 states, and 233 local governments share jurisdiction over various areas of activity on the river; the complexity and disorganization of this legal framework stifles effective action. In this Article, John R. Nolon calls for cooperative federalism and a clarification of agency roles as a remedy for this complexity. Through case studies and analysis, he explores how federal and state framework laws can be linked vertically and horizontally to facilitate disaster mitigation planning.