Preface: The First All-USGS Modeling Conference was held November 14-17, 2005, in Port Angeles, Washington. U.S. Geological Survey (USGS) participants at the conference came from USGS headquarters and all USGS regions and represented all four science disciplines-Biology, Geography, Geology, and Water. The conference centered on selected oral case study presentations and posters on current USGS scientific modeling capabilities and activities. Abstracts for these case study presentations and posters are presented here. On behalf of all the participants of the First All-USGS Modeling Conference, we appreciate the support of Dee Ann Nelson and the staff of the Olympic Park Institute in providing the conference facilities; Dr. Jerry Freilich and Dr. Brian Winter of the National Park Service, Olympic National Park, for organizing and leading the conference field trip; and Debra Becker and Amy Newman, USGS Western Fisheries Research Center, Seattle, Washington, and Tammy Hansel, USGS Geospatial Information Office, Reston, Virginia, for providing technical support for the conference. The organizing committee for the conference included Jenifer Bracewell, Jacoby Carter, Jeff Duda, Anne Frondorf, Linda Gundersen, Tom Gunther, Pat Jellison, Rama Kotra, George Leavesley, and Doug Muchoney.