25 States With The Most Historic Sites At Risk Of Flooding

Because of the deterioration and fragility of historical buildings, as well as long-term degradation of the natural environment around these structures, historic sites are often at serious risk of flooding. Stacker identified historic buildings of national significance across the U.S. located in census tracts with very or relatively high risk of flooding, using data from FEMA’s National Risk Index and the National Register of Historic Places. The National Park Service outlines six criteria for what makes a historic building on the registry nationally significant, a less rigorous designation than being considered a National Historic Landmark. FEMA calculated the risk of flooding for each census tract by combining geospatial and historic flood-event data from the National Flood Insurance Program and NOAA. For each state, a maximum of three historic sites are listed in order of their flood risk, though many states on this list have more at-risk sites in total. Colorado, Connecticut, and Idaho did not have nationally significant sites on the registry located in high-risk flood regions; as such they are absent from this list.