Caution: The pesticide use maps available from this site show the average annual pesticide use intensity expressed as average weight (in pounds) of a pesticide applied to each square mile of agricultural land in a county. The area of each map is based on state-level estimates of pesticide use rates for individual crops that were compiled by the National Center for Food and Agricultural Policy during 1990-1993 and on 1992 Census of Agriculture county crop acreage. The maps do not represent a specific year, but rather show typical use patterns over the four year period 1990 through 1993. Use intensity rates are expressed as the pounds applied per square mile of mapped agricultural land in a county. The area of mapped agricultural land for each county was obtained from an enhanced version of the 1992 USGS National Land Cover Data (NLCD). The key limitations of the data used to produce these maps include the following: (1) state use coefficients represent an average for the entire state and consequently do not reflect the local variability of pesticide management practices found within states and counties, (2) pesticide use estimates are not for a specific year, but represent typical use patterns for a four year period, (3) state pesticide use coefficients may not have been available for all states where a pesticide may have been applied to agricultural land, and therefore, are not displayed on the maps, (4) the county crop acreage is based on the 1992 Census of Agriculture and may not represent all crop acreage because of Census nondisclosure rules, and (5) agricultural land area used to calculate the pesticide use intensity and display the data was derived from 30-meter satellite remote sensing data that may over estimate or underestimate the actual agricultural land area. The maps are not intended for making local-scale estimates of pesticide use, such as estimates at the county level. Please refer to Method for Estimating Pesticide Use for a detailed discussion of how the pesticide use data were developed.