How we connect the records
Cook County Records connects records that are scattered across agencies and dates. Property releases are assembled from published datasets; municipal projects and findings are reviewed from official documents. We distinguish what a record states, what we calculate, and what remains a question.
Town boundaries and source coverage
Coverage follows municipal boundaries. The New Trier collection covers Wilmette, Winnetka, Glencoe and Kenilworth; it does not include every parcel in New Trier Township. A small number of village parcels file in Northfield Township, and each appeal follows the parcel’s own township.
Mapped parcel counts exclude condo parking and common areas and records without usable locations. County GIS does not supply outlines for every PIN; when an outline is missing, a small map marker uses the Assessor's location and does not represent a parcel boundary. Missing permits mean none in the published county feed, which may omit municipal permits; they do not prove that work was never performed. Tax estimates use each town’s configured rate basis, which is identified as sourced or approximate, and do not include individual exemptions.
From a decision to a finding
- Start with the source. Reviewed municipal calendars, agendas, minutes, budgets and project records identify the authority, date and action. An agenda is planned discussion, not proof of approval.
- Connect the sequence. A finding links at least two sources. Proposed, budgeted, awarded and paid amounts are different states; calculations retain their inputs and citations. Original date precision is preserved.
- Separate evidence from consequences. Documented steps say what a source establishes. Calculations are labeled. Possible effects and unanswered questions are interpretations, not predictions or allegations.
- Name the next check. A later contract, expenditure, inspection or completion record may confirm implementation. A record missing from our reviewed collection does not establish that no record exists.
Project locators and nearby parcels provide context; proximity does not establish an affected boundary. Shared themes between projects do not prove causation.
How property records are assembled
- County sources. The Cook County Assessor and Board of Review publish their records on the county open-data portal; Cook County GIS publishes parcel outlines; FEMA publishes flood-zone maps; the Illinois Department of Revenue publishes MyDec PTAX-203 transfer declarations; the City of Park Ridge publishes an official address-PIN point table used to join address-only city files onto those parcels. We pull the parcel universe for each municipality, then every other dataset by that exact list of parcel numbers.
- Cleaned snapshot. Newest record per parcel, outlines attached, flood zone computed by location, condo parking spaces and common areas set aside. Each dataset carries the date the county last updated it.
- Entity resolution. Taxpayer names, deed parties, permit applicants and appeal counsel become entities. Links are graded confirmed (a direct relationship in a source), probable (an administrative or name association) or inferred (a heuristic such as a shared mailing address), and the grade travels with the link. A matching name is not a unique identity or proof of title.
- Published release. The snapshot is compressed, checksummed and written to the database as an immutable release; the site switches to it in one step, so a refresh can never show a half-updated town.
- This page. Facts are labeled public record with their source and date; estimates and inferences say so. Fields that only exist on portals we do not scrape — mortgages, liens, tax delinquency — are never shown as absent; they are simply not part of this dataset.
Public record, estimate, or inferred
| Field | Class | Basis |
|---|---|---|
| PIN, address, class, lot and building size, year built, condition | Public record | Cook County Assessor parcel universe and characteristics; municipal address-PIN points, where published, join on PIN |
| Assessed land, building and total values (3 years) | Public record | Cook County Assessor assessed values — board › certified › mailed stage |
| Recorded sales: date, price, deed type, parties, document number | Public record | Cook County Assessor parcel sales |
| Transfer declaration: recorded date, instrument, use, advertised / short-sale / REO / auction flags, consideration, homestead | Public record | Illinois IDOR MyDec PTAX-203 (it54-y4c6), joined on the 14-digit PIN — additional to Assessor sales. Buyer, seller, agent, and preparer names stay on the Personal plan |
| Building permits: date, type, description, status, applicant, amount | Public record | Cook County Assessor permits (from the City) |
| Appeals: year, body, type, outcome, attorney or agent | Public record | Board of Review decisions; Assessor appeals |
| Flood zone | Public record | FEMA NFHL layer 28, by parcel location — computed once at ingest |
| Assessor taxpayer name | Public record | Assessor taxpayer name and mailing address — an administrative field, not a title search |
| Estimated market value | Estimate | Assessed total divided by an inferred class-based assessment fraction: 10% for classes 2/3 and 25% otherwise, rounded to $1,000. This is a model estimate, not an appraisal |
| Estimated annual tax | Estimate | Estimated market value × the selected town’s effective tax rate; sourced or approximate as labeled |
| Frontage and depth | Estimate | Derived from the parcel outline |
| Walk time to Metra | Estimate | Straight-line distance to the nearest station |
| Zoning district | Inferred | From assessor class, until a licensed city zoning layer is connected |
| Owner-occupancy | Inferred | Taxpayer mailing address matches the property address |
| Shared-name and address matches | Inferred | Shared surname at the same mailing address; does not establish family ties, beneficial ownership or common control |
| Research scores, comparables, scenarios and system models | Estimate | Rule-based estimates using available record fields and assumptions; limitations are described below |
What a score is
Parcel scores combine weighted assumptions about recorded building and lot characteristics, holding patterns, nearby permit activity and potential parcel groupings. Zoning and shared-name associations require independent verification. Scores are clamped 0–100 and banded low / watch / elevated / high: heuristic model outputs, not verified conditions or predictions. Some legacy source assumptions remain in their numeric calculation; corrected labels do not mean those scores were recalculated.
Building systems
Roof, HVAC, water heater, electrical, plumbing, windows and sewer take an estimated installation year from the latest matching permit, or the building’s age when no matching permit is available. Three models sit behind each — a life clock, a Weibull wear-out curve, and permit-only — and you can switch between them. These are model assumptions, not observed condition or a calibrated prediction for an individual system. None is an inspection.
Relationships
Confirmed links describe a direct relationship stated in a source, such as counsel on an appeal case. Probable links include administrative fields and a deed-party name matched to an entity; a document number identifies the deed, not a uniquely verified person. Inferred matches, such as shared mailing details, retain their supporting evidence. None of these name or address matches proves family ties, common control, beneficial ownership or wrongdoing. The graph is capped at 80,000 edges; the lowest-priority kind is trimmed first and the count is reported with each release.
Coverage and refresh
Property releases cover Park Ridge, Wilmette, Winnetka, Glencoe, Kenilworth. Each town and source has its own coverage and dates. Municipal review dates describe when we checked a source, not when every underlying record was published. This collection is selective, not exhaustive. See Park Ridge coverage and freshness.
Method versions and editorial responsibility
Cook County Records maintains these methods. September 10, 2026: address components v2 separates street identity from unit and building references; street publication requires a reviewed source dictionary; parcel indexability v1 requires current assessment provenance, a stable PIN and meaningful public context. These controls affect discovery and grouping, not the original agency record.
September 6, 2026: civic evidence edition connects decisions, commitments and subsequent records. Each claim retains its evidence date and source. A later website check does not establish a later decision, payment or completion.