ABSTRACT:Irrigated agriculture is one of the most important water‐use sectors in terms of total water diversion and consumptive use. For at least the last 25 years, improving irrigation efficiency has been a widely advocated and accepted goal. This paper uses a sample of 16 Bureau of Reclamation irrigation projects to examine the pattern of average irrigation efficiency and change in efficiency over time. In general, the highest average efficiencies are found in the arid Southwest while the lowest are found in the semi‐arid to sub‐humid Great Plains region. Over the 22‐year period of analysis, there has been no observable trend toward improvement in efficiency at any of the p