"... the National Portal is a massive, multiyear project to provide information on 4,000 historical sites, including easily searchable online access to digital images and descriptions of millions of artifacts housed in the collections of American museums, historical societies, National Parks, and other institutions across the country.
The objects being added to this national “clearinghouse” include documents, photographs, paintings and artifacts, and run the gamut from military artifacts to artworks to the tools and mementos of everyday life."
National Portal To Historic Collections from American Heritage and AASLH
Started in 2007, American Heritage and the American Association for State and Local History (AASLH) currently sponsor the National Portal To Historic Collections. According to the About page,