The California Land Conservation Act of 1965 - commonly referred to as the Williamson Act is the State's primary program for the conservation of private land in agricultural and open space use. The Williamson Act is a voluntary, locally administered program that offers preferential property taxes on lands which have enforceable restrictions on their use via contracts between individual landowners and local governments.

The Department of Conservation is the distributor and not the originator of this data. Although Government Code 51237.5 requires cities and counties to report Geographic Information System (GIS) data on or before January 30th of each year for Williamson Act contracted land in existence at the end of the preceding year, not all cities and counties have reported up to date information. Data reflects Williamson Act enrollment status as of the year stated in the file's title. Status of enrolled lands may change throughout the year. Please contact the local jurisdictions directly to obtain current site-specific information.

This data depicts land enrolled in Williamson Act and/or Farmland Security Zone contracts and does not necessarily provide information as to the location of Agricultural Preserves within each county. The data is being provided to assist in regional and statewide planning efforts. Please note this data is submitted to the state by participating counties and as such reflects the counties’ data. Although we are working to have all participating counties provide updated information, only some of the data is up to date as of the current year as some counties have not submitted data for several years. Data reflects enrollment status as of the year stated in the file's title. The most current and up to date site-specific data can be obtained from the individual participating counties as the status of enrolled lands may change throughout the year. You are encouraged to verify specific data with the individual county or counties before proceeding with any specific projects or relying on this data for in depth analysis.