This ongoing project was initiated to integrate historic geographic information system (GIS) datasets with data from recent acoustic seafloor surveys to create a Bay-wide benthic habitat characterization. Historic datasets include mainstem sediment polygons , Maryland Bay Bottom Survey polygons, and Virginia Oyster Ground Survey polygons. Mainstem sediment polygons were derived from sediment grab sample data collected by the Maryland Geological Survey and the Virginia Institiute of Marine Science from 1976 to 1984. Raw grainsize data from the two sources were merged, classified with Shepard's ternary model, and interpolated by the NOAA Chesapeake Bay Office. The Maryland Bay Bottom Survey was conducted by the Maryland Department of Natural Resources from 1974 to 1983. Bottom types were determined with patent tongs and a dragged acoustical device. The Virginia Oyster Ground Survey (Baylor survey grounds) was evaluated by the Virginia Institute for Marine Science for the suitability of oyster culture from 1978 to 1981. Bottom types were determined using probing pipes, patent tongs, and a dragged acoustical device. Recent habitat characterizations derived from side-scan sonar and acoustic seabed classification were mosaiced on top of the historical GIS layers.