National Geodetic Data Survey Explorer is provided by the National Geodetic Survey whose mission is to define, maintain and provide access to the National Spatial Reference System (NSRS).
EarthExplorer allows you to acces a wide range of image data. Search by street address, Longitude and Latitude or by time. Most data is availabel for free, put select data require free registrationa nd some are availabe for putchase.
GRAV-D (NGS) include airborne and terrestial survey information, gravity data, and gravity-based geoids or datums.
Federal Departments and Bureaus
Center for Disease Control
500 Cities: Local Data for Better Health reports city and census tract-level data, obtained using small area estimation methods, for 27 chronic disease measures for the 500 largest American cities.
