Excerpts from the report: The John Day River Basin is located in north central Oregon. The Blue Mountains and its spurs form the northern, eastern, and southern boundaries of the basin, and the divide between the lower Deschutes River and the John Day River forms the western boundary. It is about 130 miles wide at its widest point and narrows to 25 miles along the Columbia River. The longest north-south distance is 90 miles. The basin encompasses an area of about 8,000 square miles and includes major portions of Wheeler, Gilliam, Grant, and Sherman Counties and minor portions of Umatilla, Morrow, Jefferson, Wasco, Crook, Harney, and Union Counties. The climate is generally semi-arid; it is characterized by low annual precipitation, very dry summers, and low winter and high summer temperatures. The average annual precipitation varies from less than 10 inches along the lower river to more than 40 inches in the high mountains. The growing season in the major agricultural areas varies from 120 to 170 days. Forty-four percent of the basin is forested land, 44 percent is open rangeland, 11 percent is cropland, and 1 percent is devoted to other uses. Sixty-three percent of the basin is privately owned; 37 percent is publicly owned. The broad objective of the cooperative survey was to gather data and information pertinent to the use and control of water for agriculture in the basin, as well as data concerning such water-related problems as erosion, flood prevention, and drainage. Data of this kind are necessary for appraisal of present and future use of water by agriculture in relation to other water uses and for planning, evaluation, development, and operation of the various agricultural programs of Federal, State, and local agencies. Data presented herein should be of use to anyone interested in the basin's land and water resources.