U.S. land irrigated with onfarm pumped water increased by 9.5 million acres to 44.5 million acres from 1974 to 1983. Higher energy prices increased energy pumping costs from $551 million to $2.5 billion. Pump irrigators applied energy-saving technologies such as low-pressure center pivots, which alone saved about $72 million in 1983. Favorable economic conditions could lead to 3 to 4 million additional pump-irrigated acres in the water-short Great Plains by the year 2020 and significant increases in the more humid Eastern States. This report, the fourth in a series, updates the 1980 irrigation estimates and focuses on 1983 pump-irrigated farmland, prospects for irrigation, and fuel costs.