The article presents a global inventory of the extent and consumptive water use of irrigation areas, focusing on groundwater, surface water, and non-conventional sources. The inventory covers 15,038 national and sub-national administrative units, using census-based statistics and a global hydrological model to estimate water use. Globally, about 301 million hectares are equipped for irrigation, with 38% using groundwater. Total consumptive groundwater use for irrigation is estimated at 545 km³ yr⁻¹, or 43% of the total consumptive irrigation water use of 1277 km³ yr⁻¹. India, China, and the USA have the largest areas equipped for irrigation with groundwater. Groundwater use in irrigation is increasing, leading to over-exploitation in some regions. The inventory highlights the importance of groundwater in irrigation, especially in semi-arid and arid regions, and the need for better data and management to ensure sustainable water use.The article presents a global inventory of the extent and consumptive water use of irrigation areas, focusing on groundwater, surface water, and non-conventional sources. The inventory covers 15,038 national and sub-national administrative units, using census-based statistics and a global hydrological model to estimate water use. Globally, about 301 million hectares are equipped for irrigation, with 38% using groundwater. Total consumptive groundwater use for irrigation is estimated at 545 km³ yr⁻¹, or 43% of the total consumptive irrigation water use of 1277 km³ yr⁻¹. India, China, and the USA have the largest areas equipped for irrigation with groundwater. Groundwater use in irrigation is increasing, leading to over-exploitation in some regions. The inventory highlights the importance of groundwater in irrigation, especially in semi-arid and arid regions, and the need for better data and management to ensure sustainable water use.