- Geotechnical engineers design and analyze the interface between the natural and built environments, often based on uncertain and inherently variable data due to the nature of the building material, soil. Engineers must estimate the subsurface conditions at a site using historical, in-situ, and laboratory testing data. However, only discrete representative samples can be obtained during subsurface investigations and soil engineering properties can vary appreciably at a single site, both laterally and with depth. Designs based on incomplete, inaccurate or misinterpreted subsurface data can be dangerous and extremely costly, but comprehensive site investigation is also expensive, so engineers are constantly attempting to achieve an appropriate balance. To the extent possible, it is often beneficial to begin site characterization before leaving the office: information on weather conditions, geography, topography, regional geology, and adjacent structures is available for many sites. Prior borehole logs and historical subsurface tests, however, commonly remain un-aggregated, in original reports and in the respective project offices after the projects have been completed. It would therefore be beneficial to have a comprehensive database where engineers and geologists could search by location for previous subsurface explorations, tests and in-situ reports, soil engineering properties, and hazard reports. This document describes just such a database that has been developed using a geographic information system (GIS) to compile soil engineering properties for the state of Oregon. Researchers and engineers collect enormous quantities of geotechnical data from across the state as part of projects funded by the Oregon Department of Transportation (ODOT), the Cascadia Lifelines Program (CLiP), National Science Foundation (NSF), in addition to industrial projects. The Georeferenced Oregon Soil Engineering Properties Database (GOSEP) compiles existing data across projects from all over the state, including monotonic strength, laboratory characterization data, borehole logs, and in-situ test results. The database is world viewable and searchable via a web interface. Ultimately, more complete data sets facilitate better decision making and knowledge of soil engineering properties helps guide decisions about infrastructure hardening, protection, and post-disaster redeployment.