A National Historical Landmark (NHL) is a designation given by the United States government to sites that hold significant historical value. These landmarks are recognized for their importance in American history, culture, or architecture. The designation helps preserve these sites for future generations and promotes public awareness of their significance. To qualify as an NHL, a site must meet specific criteria set by the National Park Service. Examples of NHLs include historic buildings, battlefields, and archaeological sites, such as the Statue of Liberty and Gettysburg National Military Park. This designation helps protect and maintain these important pieces of American heritage.