This Butterfly Occurrence Database portrays the occurrence of butterflies in counties in New York State. Butterfly occurrence data are cumulative, so positive occurrence data do not necessarily imply current residence of the species. Most records are from the last 30 to 40 years, with a few records that date from as early as the late 1800's. These data are intended for use in publications at a scale of 1:2,000,000 or smaller. Due to the small scale, the primary use is for regional and national data display and analysis, rather than specific local data analysis. No responsibility is assumed by the U.S. Geological Survey in the use of these data.