Jurisdiction, address checks, school districts and local rules, each with its source.
Bostonia is an unincorporated community in San Diego County's East County, just north of El Cajon. The Census Bureau counted 16,882 people there in 2020. Mail goes to El Cajon, mostly ZIP 92021 with part in 92020. Because it is outside a city, County of San Diego rules apply. Nearly all of it sits inside Gillespie Field's airport influence area, parts are mapped for fire and flood hazard, and three school districts serve it, so check the exact address before you make an offer.
General information only, not legal advice. See the note near the end of this page.
Want a Bostonia real estate agent to look at a specific home with you? Karina Somenzari, REALTOR®, works with buyers and sellers in Bostonia and across San Diego County's cities and communities, in English or Portuguese; contracts and escrow documents are in English.
| Topic | What the official record shows |
|---|---|
| Status | Unincorporated. The Census Bureau counts it as a census designated place, "Bostonia CDP," outside El Cajon's city limits. The historic Bostonia neighborhood also reaches into the City of El Cajon, so this page covers the unincorporated part. |
| Population and size | 16,882 at the 2020 Census, on 1.926 square miles of land (Census Bureau, 2025 Gazetteer). |
| Location | East County, just north of El Cajon's city limits. |
| Mailing address | El Cajon, CA. Most of the area is in ZIP 92021 and part is in 92020. Bostonia is not a mailing city, so check the ZIP for the exact address. |
| Local government | The County of San Diego provides most city-type services in unincorporated areas: law enforcement, roads, parks, libraries and building permits. San Miguel Fire & Rescue lists Bostonia in its service area; use its map search to confirm the district for an address. Water and sewer providers were not confirmed, so ask the seller or the County. |
| County plan area | The County's Lakeside Community Plan area. Lakeside is a separate community with its own address. |
This page does not describe the mix of housing types or lot sizes in Bostonia, because no official source for them was confirmed. What it can do is list the checks that depend on the exact address. Karina's free property report looks up fire, flood and fault zones for an address.
If you're buying a resale home in a homeowners association (HOA), California Civil Code 4525 says the seller must give you the governing documents and a written statement of the current regular and special assessments and fees. Request them early, since your contingency period is limited. No list of Bostonia HOAs was found, so ask whether a given home has one.
Mello-Roos is the common name for a Community Facilities District (CFD), a district that levies an annual special tax on parcels inside it. The County Auditor's FY 2025-2026 list of active Mello-Roos districts shows no district for the school districts that serve Bostonia. That list can change, and it does not mean no home carries a special tax. The home's current property tax bill is the real check; it lists each special assessment with the agency's phone number. Civil Code 1102.6b also covers the notice: if the home is subject to a special tax, the seller must make a good faith effort to get the agency's disclosure notice.
CAL FIRE maps fire hazard, not risk. On its 2025 local-area map, most of Bostonia is mapped NonWildland, but parts, mainly in the north, are mapped Moderate, High or Very High. The State Responsibility Area map (land where the state is responsible for wildfire protection) shows none of Bostonia. The exact address decides which applies. The seller's Natural Hazard Disclosure report states the zone for the home, and the State Fire Marshal's page has the official map viewer.
FEMA's flood map shows parts of Bostonia in a Special Flood Hazard Area (Zone AE) and in 0.2 percent annual chance flood hazard areas. Other parts are mapped as minimal hazard. If a home is in a Special Flood Hazard Area and the mortgage comes from a federally regulated lender, flood insurance is required. Look up the address at the FEMA Flood Map Service Center.
Gillespie Field is a County of San Diego airport in the northwest corner of El Cajon. Nearly all of Bostonia is inside its Airport Influence Area. The airport land use plan addresses land use actions near the airport. On a resale, the natural hazard report tells you if the home is in an airport influence area, and if it is, the report includes a "Notice of Airport in Vicinity." The Airport Land Use Commission has a page with address mapping.
For most housing built before 1978, federal law requires the seller to disclose known lead-based paint and hazards and to give you the EPA pamphlet and a 10-day period for a lead inspection, unless you agree otherwise in writing.
Grossmont Union High School District serves the high school grades. For lower grades, Cajon Valley Union School District covers most of Bostonia and Santee School District covers part of it. Boundaries follow the exact address, so use the lookups and then confirm with the district. This page doesn't rate or rank schools.
| District | Address lookup |
|---|---|
| Grossmont Union High School District | GUHSD School Locator |
| Cajon Valley Union School District | School site locator |
| Santee School District | School Boundary Locator |
In the unincorporated area, ADUs follow County rules. The County says the property must be in the unincorporated areas of the County. On March 4, 2026, the Board of Supervisors adopted a program that allows the separate sale of ADUs in unincorporated communities through a condominium conversion process. A junior ADU (JADU) must be inside an existing or proposed house and can be at most 500 square feet. Lot, utility and fire-access limits depend on the property, so read the County ADU page and ask the County.
The County Treasurer-Tax Collector collects transient occupancy tax (TOT) in the unincorporated areas. It covers vacation and short-term rentals of any kind. Operators must register and get a TOT certificate, and the tax is currently 8% of the rent. Whether zoning allows a short-term rental on a particular lot is a separate question for County Planning & Development Services. In the City of El Cajon part of Bostonia, City rules apply instead.
Bostonia's name covers two jurisdictions. A home in the unincorporated part follows the County rules above. A home in the City of El Cajon part follows City rules for short-term rentals, ADUs and other local ordinances, so confirm which one applies before relying on anything on this page. Ask Karina or the County to look up the parcel.
MTS Routes 874 and 875 run between El Cajon Transit Center and East El Cajon via Washington Avenue, Parkway Plaza and Broadway. The timetable effective September 6, 2026 lists Kaiser Permanente Bostonia among its destinations. MTS also lists Route 815 between El Cajon Transit Center and East Main & Madison. El Cajon Transit Center is the hub for the Orange, Green and Copper trolley lines. Gillespie Field has its own Copper Line station at 1990 1/2 N. Cuyamaca St. A timetable names a destination, not a stop inside Bostonia, so check the route map for the stop you need.
No County park inside the unincorporated area was confirmed for this page. The City of El Cajon runs Bostonia Park next to the Bostonia Recreation Center on Bostonia Street, just south of the unincorporated area. Gillespie Field is the major nearby landmark.
If you own in Bostonia, several checks above become part of your disclosure package: the natural hazard report, any airport notice, HOA documents, any special tax notice and, for most homes built before 1978, the lead-paint disclosure. They go along with the other forms California requires, so this isn't a complete list. See selling a house in San Diego for the disclosure list, costs and timing, or request a free home value estimate.
Karina Somenzari, REALTOR®, is a real estate agent licensed in California (DRE# 02248263) with eXp Realty of California, Inc. She represents buyers and sellers in Bostonia and across San Diego County. You can work with her in English or Portuguese; contracts and escrow documents are in English.
To start, tell her about your plans, call 619-369-4598 or, if you're selling, ask what your Bostonia home is worth. If you'd rather talk in Portuguese, read about working with a Portuguese-speaking real estate agent.
Not entirely. The Census Bureau counts Bostonia as an unincorporated community (a census designated place) outside El Cajon's city limits. The name is also used for a neighborhood that crosses into the City of El Cajon, so a street address can be in either place. Mail goes to El Cajon, mostly ZIP 92021, with part in 92020. Look up the exact parcel to learn whether the County or the City is the local government.
The County Auditor's FY 2025-2026 list of active Mello-Roos districts shows no district for the school districts that serve Bostonia. A list can change and a parcel can carry other special taxes, so the home's current property tax bill is the real check. California Civil Code 1102.6b also requires the seller to make a good faith effort to get the agency's notice if the home is subject to a special tax.
The high school district is Grossmont Union High School District. For lower grades, Cajon Valley Union School District covers most of the area and Santee School District covers part of it. Boundaries depend on the exact address and can change, so use each district's locator and then confirm with the district.
Yes. Nearly all of Bostonia sits inside the Airport Influence Area of Gillespie Field, a County of San Diego airport in the northwest corner of El Cajon. A home in an airport influence area comes with a Notice of Airport in Vicinity in the natural hazard report. The Gillespie Field land use plan addresses land use actions near the airport.
Parts of it are. On CAL FIRE's 2025 local-area map most of Bostonia is mapped NonWildland, but parts, mainly in the north, are mapped Moderate, High or Very High. FEMA's flood map shows parts of the area in a mapped flood hazard area, including Zone AE. The answer depends on the exact address, so check the seller's Natural Hazard Disclosure report and the official maps.
In the unincorporated area, ADUs and junior ADUs follow County of San Diego rules, and the County Treasurer-Tax Collector collects an 8% transient occupancy tax on short-term rentals and requires registration. This page has not confirmed whether County zoning allows short-term rentals on a given lot, so ask County Planning & Development Services first. In the City of El Cajon part of Bostonia, City rules apply instead.
Karina offers a free, no-pressure conversation in English or Portuguese, whether you're buying or selling in Bostonia (contracts and escrow documents are in English). Send her an address and she'll walk through the checks that apply to it.