Federal onshore lands contain an estimated 20 percent of the oil and 25 percent of the undiscovered natural gas resources in the United States (U.S. Bureau of Land Management, 2006) and the BLM has identified the Upper Colorado River Basin (UCRB) as an area with high potential for continued energy development (U.S. Bureau of Land Management, 2002). The UCRB drains portions of Arizona, Colorado, New Mexico, Utah, and Wyoming and is part of the largest river basin in the southwestern United States. A significant volume of known and potential oil and gas reserves lies in the sedimentary basins of the UCRB (Huffman, 1995; U.S. Geological Survey 2002a; U.S. Geological Survey 2002b; U.S. Geological Survey 2002c) and an average of 4,527 wells per year was started on Federal land in the five UCRB states in fiscal years (FY, October 1 to September 30) 2006 and 2007 (U.S. Bureau of Land Management 2008). An average of 2,462 wells per year were drilled between FY 2000 and 2005. 1,284 wells were drilled per year on average in the preceding 10 year period from FY 1990 to 1999. Increased drilling activity has raised concerns that land disturbance from drilling activity may have an affect on surface water quality in the basin. Existing and planned land disturbance data are not regularly or consistently compiled at the state or regional level. Regional-scale compilation, synthesis, and analysis of data defining energy development- related land disturbance and water quality in the UCRB may help to improve understanding of the potential cumulative effects of current and projected energy development on land cover changes in the basin. The location of known oil and gas wells was compiled from state oil and gas databases and merged into a single oil and gas well dataset for the UCRB. The reported status of each well was used to classify the well into two categories: disturbed or not disturbed. Disturbed wells are likely associated with land disturbance. The classified wells were used to estimate the location and extent of energy related land disturbance in the basin. References: Huffman, A.C., Jr., 1995, Paradox Basin Province: U.S. Geological Survey 1995 National oil and gas assessments, accessed April 2009 at http://certmapper.cr.usgs.gov/data/noga95/prov21/text/prov21.pdf U.S. Bureau of Land Management, 2002, Resourceful management of our natural resources, accessed April 2009 at http://www.blm.gov/pgdata/etc/medialib/blm/wo/Communications_Directorate/general_publications/mgmt.Par.6587.File.dat/handout_02.pdf U.S. Bureau of Land Management, 2006, Scientific inventory of onshore federal lands' oil and gas resources and the extent and nature of restrictions or impediments to their development: Energy policy and conservation act phase II inventory, accessed October 2007 at http://www.blm.gov/epca/ U.S. Bureau of Land Management, 2008, Oil and Gas Statistics, accessed February 2009 at http://www.blm.gov/wo/st/en/info/newsroom/Energy_Facts_07/statistics.html U.S. Geological Survey, 2002a, Assessment of undiscovered oil and gas resources of the Uinta-Piceance Province of Colorado and Utah, 2002: U.S. Geological Survey Fact Sheet 026-02, accessed April 2009 at https://pubs.usgs.gov/fs/fs-0026-02/fs-0026-02.pdf U.S. Geological Survey, 2002b, Assessment of undiscovered oil and gas resources of the San Juan Basin Province of New Mexico and Colorado, 2002: U.S. Geological Survey Fact Sheet 147-02, accessed April 2009 at https://pubs.usgs.gov/fs/fs-147-02/FS-147-02.pdf U.S. Geological Survey, 2002c, Assessment of undiscovered oil and gas resources of the Southwestern Wyoming Province, 2002: U.S. Geological Survey Fact Sheet 145-02, accessed April 2009 at https://pubs.usgs.gov/fs/fs-145-02/FS-145-02.pdf