The New Madrid Seismic Zone, also known as the Reelfoot Rift or the New Madrid Fault Line, is a major seismic zone in the Southern and Midwestern United States stretching to the southwest from New Madrid, Missouri.

The New Madrid fault system was responsible for the 1812 New Madrid Earthquake and has the potential to produce damaging earthquakes on an average of every 300 to 500 years. Since 1812 frequent smaller intraplate earthquakes (earthquakes within a tectonic plate) were recorded for the area.

The seismic zone covers parts of five U.S. states: Illinois, Missouri, Arkansas, Kentucky and Tennessee.