ZIP 61531 falls in Fulton County, Illinois, where we hold 1 septic-related documents. We have not classified septic-versus-sewer status for this county, and we do not have a per-ZIP parcel count -- see the county page for what we hold and where the records are kept.
ZCTA 61531 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) |
|---|---|---|---|---|
| Fulton County, Illinois | 63% | 1 | — | — |
| Knox County, Illinois | 23% | — | — | — |
| Peoria County, Illinois | 14% | 2 | — | — |
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 have not measured septic-versus-sewer status for this county yet.
ZIP 61531 spans 3 counties: Fulton County, Illinois, Knox County, Illinois, Peoria County, Illinois.