Irrigation and drainage have played central roles in the remarkable success of American agriculture. Settlement of the American West was tied closely to irrigation, and drainage in humid regions makes possible the high production of food and fiber we know today. Irrigation is also vital to crop production throughout the Midwest, into the South, and in many Eastern States, especially Florida. Urban irrigation now comprises a large component of the irrigation market—for landscaping, golf courses, athletic fields, and other recreational uses. Irrigation continues to expand nationally, although acreages have declined in some states due to competing demands. As a heavy water user, irrigated agriculture is but one of many needs for water, energy, and land resources. At the same time, the growing global economy and world population are placing greater demands on irrigated agriculture to provide food and fiber. Conditions such as these inevitably mean changes in public policy and programs that manage and allocate water. Policymakers at all levels face increasing demands for water— for food and fiber, urban and environmental purposes, and Native American claims, as well as for retaining U.S. global competitiveness in agriculture.