The Monitoring Trends in Burn Severity (MTBS) project, sponsored by the Wildland Fire Leadership Council (WFLC), aims to assess the environmental impacts of large wildland fires and identify trends in burn severity across the United States. The project, a collaboration between the U.S. Geological Survey (USGS) and the U.S. Department of Agriculture Forest Service (USDA-FS), uses Landsat data and the differenced Normalized Burn Ratio (dNBR) algorithm to map and assess burn severity for fires greater than 202 hectares (500 acres) in the east and 404 hectares (1,000 acres) in the west since 1984. The project will generate data, maps, and reports to support policy-making, resource management, and research at local, state, and national levels. The first annual report for 2004 fires has been completed, and all data will be publicly available on a web site. The project will also serve four primary user groups: national policymakers, field managers, project managers for existing databases, and academic and agency researchers. The methodology involves compiling a fire history database, selecting and processing Landsat scenes, and mapping fire severity and perimeters using dNBR and RdNBR algorithms. The results of the 2004 fires show that 39% of the mapped area fell into high and moderate severity classes, with Alaska being the most affected region. The project will provide valuable data for understanding burn severity trends and supporting research and operational activities.The Monitoring Trends in Burn Severity (MTBS) project, sponsored by the Wildland Fire Leadership Council (WFLC), aims to assess the environmental impacts of large wildland fires and identify trends in burn severity across the United States. The project, a collaboration between the U.S. Geological Survey (USGS) and the U.S. Department of Agriculture Forest Service (USDA-FS), uses Landsat data and the differenced Normalized Burn Ratio (dNBR) algorithm to map and assess burn severity for fires greater than 202 hectares (500 acres) in the east and 404 hectares (1,000 acres) in the west since 1984. The project will generate data, maps, and reports to support policy-making, resource management, and research at local, state, and national levels. The first annual report for 2004 fires has been completed, and all data will be publicly available on a web site. The project will also serve four primary user groups: national policymakers, field managers, project managers for existing databases, and academic and agency researchers. The methodology involves compiling a fire history database, selecting and processing Landsat scenes, and mapping fire severity and perimeters using dNBR and RdNBR algorithms. The results of the 2004 fires show that 39% of the mapped area fell into high and moderate severity classes, with Alaska being the most affected region. The project will provide valuable data for understanding burn severity trends and supporting research and operational activities.