A National Historic Site (NHS) is an area designated by the government that is home to a historically significant feature. There are 90 sites in the U.S., 78 of which are managed and preserved by NPS. Some of the remaining 12 sites are privately owned and the owners of those sites are able to ask for assistance from the government to help with preservation.
Some of the sites are preserved properties of major historical figures like Andrew Johnson, John Muir and Edgar Allen Poe. Examples of other sites include preserved settlements and commemorations of the transcontinental railroad.
The NHS classification is commonly thought to be synonymous with a National Historic Park or a National Historic Landmark, but all three are separate labels. All historic places in the U.S., including places from the above categories, are listed on the National Register of Historic Places (NRHP). The NRHP has more than 80,000 properties listed, including everything from buildings to objects; most are not managed by NPS.