High-Resolution (1 km) Cropland Irrigation Percentage Dataset for the Conterminous United States from 1890 to 2023

The U.S. Cropland Irrigation Percentage (USCIP-1km) is a 1 km resolution dataset detailing the distribution of irrigated cropland in the conterminous United States (CONUS) from 1890 to 2023. The cropland irrigation percentage was estimated and reconstructed using a machine learning method based on collected water support infrastructure records (irrigation dams, canals, wells, and water rights) and climate and environmental datasets. USCIP-1km is evaluated using aggregated county-level statistics, showing strong agreement (R²=0.95 at the county level) with a mean area error of less than 10%. Analysis shows the CONUS irrigated area expanded from less than 1.2 million ha to more than 22.2 million ha from 1890 to 2023. From the 1960s to the 2020s, the distribution of irrigated land in the United States showed a clear eastward trend; the irrigated area decreased by over 2.5 × 10⁴ km² in the west, while it increased by more than 3.0 × 10⁴ km² in the east. The total national irrigated area peaked at 1.75 × 10⁵ km² in the 2000s and then declined. USCIP-1km will help promote sustainable agricultural water management and facilitate hydro-climatic modelling.