Limnogeology is the study of modern lakes and lake deposits in the geologic record. Limnogeologists have been active since the 1800s, but interest in Limnogeology became prevalent in the early 1990s when it became clear that lake deposits contain continental environmental and climate records. A society that is focused on Limnogeology would allow greater communication and access to research on these important subjects and contribute to providing sound science used to understand rapid global changes in our modern world; thus the International Association of Limnogeology was founded in 1995 at the first International Limnogeology Congress (ILIC) held in Copenhagen, Denmark.

The Sixth International Limnogeology Congress (ILIC6) was held in Reno, Nevada, from June 15–19, 2015. The ILIC meetings have been held every 4 years since the first meeting in1995 and were subsequently convened in Brest, France (1999), Tucson, USA (2003), Barcelona, Spain (2007), and Konstanz, Germany (2011). The Congress in Reno, USA marks the second time the Congress has been held in the United States and more than 150 scientists from every part of the world participated.

As part of the Congress, ILIC6 included pre- and post- Congress field trips, the descriptions of which are included as separate trips in this Open-File Report. Trip 1 provides information on the pluvial and post-glacial Lakes of the eastern Great Basin, led by Paul Jewell, University of Utah, Ben Laabs, State University of New York-Geneseo, Jeff Munroe, Middlebury College, and Jack Oviatt, Kansas State University. Trip 2 contains information on the lake sequences of closed-basin lakes in the Eocene Green River Formation in Wyoming, led by Michael Smith, Northern Arizona University and Jennifer Scott, Mount Royal University. Trip 3 provides the background for the field trip to Pleistocene and modern lakes in the Great Basin of North America that was led by Susan Zimmerman, Lawrence Livermore National Laboratory, Ken Adams, Desert Research Institute, and Michael Rosen, U.S. Geological Survey. Trip 4 contains the information for a trip to the modern lakes in Lassen National Park that was led by Paula Noble and Kerry Howard, both from the University of Nevada, Reno.

The U.S. Geological Survey has sponsored each ILIC that has been held in the United States because of the importance of understanding paleoclimate and contaminant histories of lakes, two main themes of the Congress. This field trip guide provides a permanent record of some of the wide variety of studies that are being conducted in modern lakes and ancient lake deposits in western North America, and it provides a starting point for any one desiring to visit these exceptional sites or begin work in these areas.