This aggregate resource database contains information pertaining to the Washington Geological Survey’s aggregate resource inventory efforts. Aggregate resources are produced by mining or quarrying sand, gravel, and bedrock. Aggregate is used in the manufacturing of concrete, asphalt, and other critical materials for our roads, homes, businesses, and bridges. This database includes aggregate resource areas (polygon data), materials testing results (point data), and surface mining sites used at the time of analysis (point data). Aggregate resource areas are classified as either Demonstrated, Inferred, Speculative, or Not a Resource. These classifications are made based on information from geologic maps, subsurface records, materials testing results, mining activity, and other available data. Demonstrated and Inferred sand and gravel resources are further grouped into thickness classifications based on available average thickness data. We provide materials testing and surface mine site point data for view on the Portal map to provide further insight into the aggregate resource areas. The full download package will include additional data not on display here on the Portal: Subsurface Interpretation table, Data Sources table and Data Sources spatial data.