National Register of Historic Places listings in Harford County, Maryland

This is a list of the National Register of Historic Places listings in Harford County, Maryland.

This is intended to be a complete list of the properties and districts on the National Register of Historic Places in Harford County, Maryland, United States. Latitude and longitude coordinates are provided for many National Register properties and districts; these locations may be seen together in a map.

There are 80 properties and districts listed on the National Register in the county, including one National Historic Landmark called Sion Hill.

This National Park Service list is complete through NPS recent listings posted April 4, 2025.