National Register of Historic Places listings in Ada County, Idaho

This is a list of the National Register of Historic Places listings in Ada County, Idaho.

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

There are 156 properties and districts listed on the National Register in the county, including 1 National Historic Landmark. More may be added; properties and districts nationwide are added to the Register weekly.