Purple loosestrife is considered an invasive species. Its displacement of native species in wetlands has led to the loss of suitable habitat for wildlife. This data set contains county-level distribution information for Purple loosestrife (scientific name - Lythrum salicaria) in the United States. The collection year of the specimen is included. These data come from the U.S. Department of Agriculture's Natural Resources Conservation Service's PLANTS Database. This data set portrays the county-level distribution of Lythrum salicaria (common name - purple loosestrife) in the United States of America. These data come from the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service's PLANTS Database, which is the de facto Federal standard for information about the distribution and nomenclature of U.S. plants. These data are intended for geographic display and analysis at the national level, and for large regional areas. The data should be displayed and analyzed at scales appropriate for 1:2,000,000-scale data. The U.S. Geological Survey assumes no responsibility for the use of these data.