The Sonoma County Landmarks Commission was established on April 23, 1974 under Ordinance No. 1768, the same ordinance that provided the procedure for designation of Historic Structures (i.e., Historic Landmarks) and Historic Districts. The Ordinance establishes that the Commission shall consist of one resident from each Supervisorial District, appointed by the Board of Supervisors. The County Permit & Resource Management Department (PRMD) assigns one Staff to the Commission.
As stated in the By-Laws, the purpose of the Landmarks Commission is:
"To protect those structures, groups of structures, sites, and areas that are reminders of past eras, events and persons important in local, state, or national history, or which provide significant examples of architectural styles of the past, or which are unique and irreplaceable assets to the County and its communities."