Spheres of Influence

Sonoma LAFCO is responsible for establishing, amending, and updating spheres of influence for all cities and special districts within Sonoma County. A Sphere of Influence is defined as the probable physical boundary and service area of a local agency. Territory must be within a city or district’s sphere of influence to be considered for annexation to that city or district.

Factors considered in a sphere of influence review focus on the current and future land use, the current and future need and capacity for public facilities and services and the existence of any social or economic communities of interest. Establishment of a sphere of influence helps to:

• Ensure efficient provision of services
• Discourage urban sprawl and the premature conversion of agricultural and open space lands and prevents overlapping jurisdictions
• Avoid duplication of services

 State law requires LAFCOs to, as necessary, review and update spheres every five years. Any interested party may request Sonoma LAFCO consider a sphere of influence amendment during, or in advance of, its regular review and update schedule.

• Spheres of Influence Maps for Cities
• Spheres of Influence Maps for Special Districts