The effects of wildland fire on communities have become more intense, frequent, and far-reaching. Increased development in the wildland urban interface means higher wildfire risk and more suppression needs, costing billions every year. A comprehensive approach to preparedness and mitigation is an effective way to address increasing suppression costs and reduce risk to communities. The Wildland Urban Interface Wildfire Mitigation Desk Reference Guide is designed to provide basic background information on relevant programs and terminology for those, whether community members or agency personnel, who are seeking to enhance their community's wildfire mitigation efforts. Mitigation happens at all levels - local, state, tribal, and federal. A combined approach helps achieve fire adapted communities. Individuals, communities, and organizations working together to share and leverage resources and build partnerships are the keys to success. This guide defines terms and identifies resources that are useful in mitigation planning efforts for all lands. The four primary objectives of this reference guide are to: Provide a reference to assist with integrating wildland urban interface mitigation principles into national wildland fire training; promote common wildfire mitigation language and culture; establish an authoritative source for wildland urban interface mitigation information; and provide consistent definitions for use by all media.