Heritage Index is an independent resource that makes public heritage and cultural datasets easier to find, understand, and cite. It organizes information into searchable directories with concise summaries, consistent fields, stable links, and references to primary sources when available. Its collections support researchers, students, and curious visitors, presenting essential details in a clear format while preserving official identifiers for accurate reference. Heritage Index is not affiliated with the National Park Service or the official National Register of Historic Places; its content is compiled from public sources for research and exploration.

The site features a nationwide directory of National Register listings, covering historic buildings, districts, sites, structures, and objects, with information on location, dates, categories, significance, and source documents. Its U.S. museums directory includes cultural institutions such as art museums, botanical gardens, historical societies, and science museums, with browsing by location and type. Additional directories cover dams and water-control structures, with public safety and infrastructure data, and fire and emergency service stations, including municipal, volunteer, airport, and combined facilities.