Using Landsat imagery, the Monitoring Trends and Burn Severity (MTBS) project delineates fire perimeters and estimates the severity of fire effects upon the landscape. All known large historical fires dating back to 1984 have been mapped by the USGS and the U.S. Forest Service (USFS) Remote Sensing Applications Center (RSAC). The burn severity assessments are used to plan mitigation, recovery, and other land management activities; and in research to estimate short- and long-term impacts of fire at local, regional, and national scales. Over 15,000 fires from 1984 to 2010 from all 50 states have been mapped. For each fire, pre- and post-fire Landsat imagery is selected and processed to delineate a perimeter and highlight the changes in vegetation that occurred due to fire. All processed fires are available for download at http://mtbs.gov. This information will be supplemented as each agency makes preparations to map fires from 2011 and beyond.