ZIP 83120 falls in Bonneville County, Idaho, where we hold 7,431 parcels measured as septic county-wide and 32,524 on sewer. We do not have a per-ZIP parcel count for this county, so this is the county total, not a count specific to ZIP 83120.
ZCTA 83120 is not entirely inside one county. Land-area share is from the 2020 Census ZCTA-to-county relationship file.
| County | Land in this ZIP | Documents held | On septic (county) | On sewer (county) |
|---|---|---|---|---|
| Bonneville County, Idaho | 71% | 43 | 7,431 | 32,524 |
| Caribou County, Idaho | 19% | — | 1,702 | 1,780 |
Land-area overlap is from the 2020 Census Bureau ZCTA5-to-county relationship file, not an estimate of ours. Parcel and document counts are rows we hold, not a survey of every property in the ZIP. Last verified 2026-09-01.
We hold 7,431 parcels measured as septic for Bonneville County, Idaho as a whole, not broken out by ZIP.
ZIP 83120 spans 2 counties: Bonneville County, Idaho, Caribou County, Idaho.