In 2006, the U.S. Geological Survey (USGS), in cooperation with the Wyoming Department of Agriculture, sampled five surface-water sites in Wyoming-three in the Bighorn River Basin (BRB) and two in the North Platte River Basin (NPRB) (fig. 1). The purpose of the sampling was to describe the occurrence of pesticides in these basins during three different times of the year. This fact sheet presents the results of the sampling.