The DWH SDM Segment dataset contains the information on the physical attributes of the shoreline segments considered in the Shoreline Deposition Model (SDM). The SDM estimates the number of birds that died along the shoreline of the northern Gulf of Mexico using data on the birds collected (DWH Collected Birds Dataset), the search effort undertaken by the Trustees (DWH Wildlife Search Effort Dataset), and parameters such as the number of birds likely missed by searchers (searcher efficiency) and how long carcasses remain on the shorelines (carcass persistence) to estimate the rate at which carcasses deposit along the shorelines. In order to estimate avian mortality in specific locations and to allow for the use of habitat-specific calculations, the shoreline of interest was delineated into many segments, each covering only one habitat type. Since this information is spatial in nature, the DWH SDM Segment dataset was developed in GIS, and is contained within a GIS file (ArcGIS shapefile) as well as in tabular form in a spreadsheet. The dataset does not contain information on the actual search events for the segments or birds collected on the segments; these data are tabulated in the DWH Wildlife Search Effort dataset and DWH Collected Dead Birds and DWH Collected Live Birds dataset, respectively.