This data release contains projections of future water demand for the Western USA at the county level. This data is part of the project "Changes to Watershed Vulnerability under Future Climates, Fire Regimes, and Population Pressures" (https://www.sciencebase.gov/catalog/item/531dc54de4b04cb293ee7806), and is the product of an analysis that determined where populations are changing, and how that change could affect residential and agricultural water withdraws from surface and ground water. Agricultural water use was derived from the Cropland Data Layer (CDL) of the National Agricultural Statistics Service, while residential water use was drawn from the USGS (Maupin et al. 2014). The scenarios follow four Intergovernmental Panel on Climate Change Special Report on Emission Scenario (IPCC SRES) storylines (A1, A2, B1, B2) and project changes for the periods ending in 2050 and 2100. Integrated Climate and Land Use (ICLUS) Data from Bierwagen et al. (2010) was used to project population change according to the SRES storylines. By using the same storylines, coherent population and climate scenarios can be projected that are the product of both changing populations and future climates. Bierwagen et al. (2010). National housing and impervious surface scenarios for integrated climate impact assessments. DOI: https://doi.org/10.1073/pnas.1002096107 Maupin et al. (2104). United States Geological Survey (USGS) Water-use Intensity Data. DOI: http://dx.doi.org/10.3133/cir1405