A national historical park ("National Historical Park" or "National Historic Park") and a national historic site ("National Historic Site") are the designations used in North America to protect areas of historical importance, generally designated by a governing body that is responsible for overseeing those historic resources. Academic research has usually been carried out on them and it is considered that they have an important collection of sites or resources that speak of important aspects of a place or historical personality.

In the United States, most National Historical Parks and National Historic Sites are managed by the National Park Service. Some federally designated sites are privately owned, but are authorized to apply for assistance from the National Park Service as affiliated areas.

A national historic site generally has a single historic feature that is the cause of its protection. Derived from the Historic Sites Act of 1935, some historic sites were established by the United States Secretary of the Interior, but most have been authorized by acts of Congress. A National Historical Park generally extends beyond individual properties or buildings, and its resources are a mix of history and sometimes important natural features.

Since October 15, 1966, all historic areas that belong to the National Park System—sites and parks—are automatically included in the National Register of Historic Places.

As of April 2009 in the National Park System there were 45 national historic parks (comprising 486.9 km²), 77 national historic sites (comprising 87.7 km²), and one international historic site.[1]​.

In the United States, sites are "historical," while parks are "historical." The National Park Service explains that a site may be inherently historic, while a park is a modern legal invention. As such, a park itself is not "historic," but can be called "historic" when it contains historic resources. These are the resources that are historical, and not the park.[2]​.

In contrast, these semantic distinctions do not affect designations in Canada, where National Historic Parks were created at the national level and describe historic properties managed by Parks Canada. In the past, a "national historic park" title was applied to all lands and buildings owned and operated as historic sites in the national park system, regardless of area or complexity of resources. The title did not apply to historic properties within the national park boundaries, which are administered by the park itself, and did not count as separate units of the park system.