The soil landscapes of Northeast U.S. are a diverse assemblage of physiography, bedrock and surficial geology, plant communities, and microclimates, which also contribute to the diverse array of soil climate regimes and agroecosystems. Topography, elevation, latitude, and proximity to large water bodies are major factors in the occurrence of soil climate regimes and their variability. Strong orographic processes along the Allegheny Plateau, Tughill Plateau, Catskills, Adirondacks, Green Mountains, and Presidential Range produce soil landscapes of high precipitation 1250 mm (>50 in) and distinct rain shadows in leeward areas. Maritime influences from the Atlantic Ocean and degraded tropical storms from the Gulf of Mexico often stall and produce large rainfall events over the Appalachians that trigger floods and landslides, reshaping soil landscapes. Although the Northeast soil landscapes are dominantly Udic soil moisture regimes, Aquic regimes are associated with tidal wetlands, depressions in glacial till and outwash plains, and high elevation bogs and swamps of the Appalachians. Newhall Simulation Model runs of high elevation weather stations in the Northeast indicates the occurrence of Perudic soil moisture regimes coupled with Mesic, Frigid, Cryic, and Pergelic soil temperature regimes. In earlier work by Cunningham and Ciolkosz (1983) and Smith (1984), the occurrence of these soil temperature regimes coupled with Perudic environments at the higher elevations in the Northeast was not considered. Similarly, our research also addresses the occurrence of Ustic and Xeric soil moisture regimes during drought events and their higher frequencies associated with rain shadow positions. Our research connects these soil climate regime histories to multiple scales of soil resource information—the Soil Survey Geographic Database (SSURGO), State Soil Geographic Database (STATSGO), Common Resource Areas, and Major Land Resource Areas map units. A terrain regression modeling approach in ArcGIS was coupled with the Newhall Simulation Model (NSM; Van Wambeke et al. 1992) to generate surfaces of soil temperature and moisture regimes, soil biological windows, and agroclimatic parameters (growing degree-days, frost-free period, and temperature minima). Initially, maps were based upon 1971 to 2000 normals. Later, long-term (>60 y) weather stations (NOAA's Historical Climatology Network) in the Northeast U.S. and adjoining states were modeled on individual years to build frequencies of soil climate regimes and droughts, as well as identify shifts in time and space. Agricultural and forest research locations in the Northeast were compiled for this study to build agroecozones and to compare growing season environments. As part of this project, the Newhall Simulation Model was updated for web-delivery and re-calibrated using the USDA/NRCS Soil Climate Analysis Network sites in the Northeast. The subcalculations from the Newhall Simulation Model, which are criteria in the Soil Taxonomy (Soil Survey Staff, 2003) definitions of soil temperature and moisture regimes, were derived for new agronomic applications. Similarly, these subcalculations for mean annual water balance, summer water balance, and soil biological windows can be applied to soil genesis studies. This web-based Soil Climate Regime Atlas of the Northeast U.S. has been implemented using an advanced interactive Web-map based interface that allows users to spatially explore the full range of soil temperature and moisture regimes and ancillary climatic parameters. The Atlas is available online at the Center for Environmental Informatics, Earth and Environmental Systems Institute located at The Pennsylvania State University (www.cei.psu.edu).