Remote communities at the edges of San Diego County’s fire landscape and into the adjacent Riverside County backcountry
What Ring 3 means
The communities in this section sit at the furthest reaches of the fire landscape covered by this site. Borrego Springs is San Diego County’s easternmost desert community, completely surrounded by Anza-Borrego Desert State Park. Anza, Aguanga, and Idyllwild are in Riverside County — included here because they share the same fire landscape, the same California wildfire law framework, and the same professional community as San Diego’s backcountry. Each page clearly identifies the applicable jurisdiction.
Ring 3 communities share the characteristic of remoteness — limited access, extended emergency response times, dependence on utility infrastructure that crosses fire-prone terrain, and limited suppression resources relative to the scale of fire events this landscape can produce. The Cranston Fire cut power and water to Anza for two weeks. The Nixon Fire burned 5,000 acres in the hills above Aguanga in days. The Cranston Fire threatened 5,000 structures in Idyllwild simultaneously. Borrego Springs is surrounded on all sides by 650,000 acres of state park wildland.
For Ring 3 property owners, the gap between a manageable fire event and a catastrophic one is often a function of individual property preparation — because when fire is remote and resources are stretched, the condition of your specific property perimeter may be the only variable that is actually within your control at the moment fire arrives.
A note on Riverside County communities
Anza, Aguanga, and Idyllwild are in Riverside County, not San Diego County. The enforcing agencies are CAL FIRE’s Riverside Unit and the Riverside County Fire Department — not San Diego County agencies. California wildfire law (PRC 4291, AB 38, Civil Code 1102.19, Insurance Code 2644.9) applies equally in both counties. The community pages identify the correct local contacts for each Riverside County community.
Communities in Ring 3
- Anza — A high desert community in Riverside County’s Anza Valley at approximately 3,900 feet, affected by the 2018 Cranston Fire and the June 2025 Cahuilla Fire that burned near Highway 371 in the community itself.
- Aguanga — A small Riverside County community on the San Diego County line, origin point of the October 2023 Highland Fire and directly affected by the August 2024 Nixon Fire that burned over 5,000 acres in the immediate area.
- Idyllwild — A mountain resort community of approximately 12,000 residents at 5,400 feet in the San Jacinto Mountains, completely surrounded by San Bernardino National Forest, directly threatened by the 2018 Cranston Fire.
- Borrego Springs — San Diego County’s desert community, completely surrounded by Anza-Borrego Desert State Park — the largest state park in California — with a fire environment defined by desert transition terrain rather than mountain chaparral.
Key contacts for Ring 3
- CAL FIRE San Diego Unit — fire.ca.gov — Borrego Springs (San Diego County SRA)
- Riverside County Fire Department — rvcfire.org — Anza, Aguanga, Idyllwild
- CAL FIRE Riverside Unit — fire.ca.gov — Riverside County SRA
- FHSZ Viewer — https://experience.arcgis.com/
Disclaimer
Content on this page and the linked community pages is provided for educational purposes only and does not constitute legal advice. Laws, regulations, and FHSZ designations change — always verify current requirements with the appropriate fire agency or a licensed attorney. Last reviewed March 2026.