The most recent compilation of data on agriculture in the United States is from the 1998 United States Department of Agriculture Fact Book. There are 10 major farm production regions in the United States which differ in soils, slope of land, climate, distance to market, and storage and marketing facilities. The Pacific region includes the three Pacific Coast States plus Alaska and Hawaii. Farmers in Washington and Oregon specialize in raising wheat, fruit, and potatoes. Vegetables, fruit, and cotton are important in California. Cattle are raised throughout the region, and California leads the Nation in milk production. In Hawaii, sugarcane and pineapples are the major crops. The United States has the largest fed-cattle industry in the world. In Idaho, Eastern Washington, the Central and Imperial Valleys of California are vast irrigated areas and feedlots. The Corn Belt, Lake States, and Northern Plains accounted for 78 percent of total U.S. hog production in 1950 and in 1980, but in the last few decades, the Southern states and isolated areas of the West have become increasingly important areas of hog production. http://www.ers.usda.gov/briefings Agriculture is the major source of sediment, nutrients, herbicides, insecticides, antibiotics, and pharmaceuticals released into aquatic ecosystems. Nationally, agriculture is the leading source of pollution in 57 percent of river miles, 30 percent of lake acres (excluding the Great Lakes), and 15 percent of estuarine waters found to be impaired. The U.S. Geological Survey, National Water Quality Assessment Program provides information regarding how application of fertilizers, manure and pesticides have degraded surface and shallow ground water in agricultural areas, and EPA's Water Quality Inventory contains pollutant information as required under Section 305(b) of the Clean Water Act.