The Russian River Watershed (RRW) covers about 1300 square miles (without Santa Rosa Plain) of urban, agricultural, and forested lands in northern Sonoma County and southern Mendocino County, California. Communities in the RRW depend on a combination of Russian River water and groundwater to meet their water-supply demands. Water is used primarily for agricultural irrigation, municipal and private wells supply, and commercial uses - such as for wineries and recreation. Annual rainfall in the RRW is highly variable, making it prone to droughts and flooding from atmospheric river events. In order to better understand surface-water and groundwater issues, the USGS is creating a Coupled Ground-Water and Surface-Water Flow Model (GSFLOW; Markstrom and others, 2008) of the RRW. This model will include climate, geology, surface-water, groundwater, and land-use data. This data release is part of the larger Russian River Integrated Hydrologic Model (RRIHM) community of data releases (https://www.sciencebase.gov/catalog/item/62ffdd40d34ed6dc55924a4b). This is a shapefile of the Russian River Integrated Hydrologic Model (RRIHM) model grid. The attribute table specifies the active and inactive model grid cells in each of the three model layers. It also specifies the elevations of the top of the first model layer and the bottoms of all model layers. This information is used in the model to define the spatial extent and thickness of each of the model layers.