USGS Maps and Aerial Photo Images Online

This portal provides links to United States Geological Survey (USGS) partner sites where users can locate a variety of maps and imagery. Items include digital products such as orthophoto quadrangles (DOQ), digital raster graphics (DRG), elevation models (DEM), and digital line graphics (DLG). There are also links to interactive map applications, "flyovers", and art-quality reproductions of maps and imagery. Some materials are free; others are available for purchase. Educational levels: Middle school, High school, Undergraduate lower division