Cook County Value

12444 Thornberry Dr Lemont, IL 60439

4 bed / 3 bath, 4,439 sqft, built 2009, in Lemont. Assessor market value for 2026: $1,040,000.

Cook County account 22303100180000

Assessor market value
$1,040,000
Tax year 2026 · before exemptions; the assessed value on your notice is 10% of it
Living area
4,439 sqft
$234 per sqft
Year built
2009
Average quality

Compare this assessment

Start with the county value and property facts, then review appraisal comps, recent sales, and prior-year changes to decide whether the assessment is worth challenging. The comps on this page are free to review; email sign-in is only used to save a printable report.

For nearby context, browse ZIP 60439 and Lemont assessment pages.

Local guide: Lemont Township 2026 Property Tax Appeal Guide.

Appeal deadlines

For Lemont, appeals to the Assessor closed . Board of Review dates for Lemont have not been published yet.

Deadline rule: Set by township: file with the Assessor by your township's last file date, and with the Board of Review while your township is open there. Evidence is reviewed by the Cook County Assessor's Office or, in a separate appeal, by the Cook County Board of Review. Dates checked against the official source.

Assessment snapshot

These public CCAO records highlight what may be worth checking before you file.

  • Assessment changeThe assessor market value increased 37.9% from $754,350 in 2025 to $1,040,000 in 2026.
  • Assessor market value per square footThe current public record shows about $234 per square foot before any comparable-property adjustments.
  • Nearby comparison areaThis page starts the equity review with public records for the Lemont neighborhood and ZIP 60439.
  • Neighborhood value signalAmong 380 residential records in the same neighborhood, the average assessor market value is about $246 per square foot.
  • Area year-over-year signalNearby residential records with prior-year values moved about +25.8% on average.

Comparable assessments

Similar public appraisal records selected for this property's equity comparison.

  • 12524 Thornberry Dr Lemont, IL 60439
    4,434 sqft | $221/sqft | built 2009 | Similar size (4,434 vs 4,439 sqft); Built same year (2009); Similar lot size (13,408 vs 14,058 sqft)
    $980,000
  • 12473 Briarcliffe Dr Lemont, IL 60439
    4,641 sqft | $220/sqft | built 2005 | Similar size (4,641 vs 4,439 sqft); Similar age (2005 vs 2009); Similar lot size (13,956 vs 14,058 sqft)
    $1,020,010
  • 13591 Cambridge Dr Lemont, IL 60439
    4,463 sqft | $246/sqft | built 2002 | Similar size (4,463 vs 4,439 sqft); Similar lot size (13,973 vs 14,058 sqft); Same quality (Average)
    $1,100,000
  • 12450 Briarcliffe Dr Lemont, IL 60439
    4,250 sqft | $261/sqft | built 2012 | Similar size (4,250 vs 4,439 sqft); Similar age (2012 vs 2009); Similar lot size (14,559 vs 14,058 sqft)
    $1,110,000
  • 13845 Oak Tree Ln Lemont, IL 60439
    4,442 sqft | $216/sqft | built 2000 | Similar size (4,442 vs 4,439 sqft); Similar lot size (15,000 vs 14,058 sqft); Same quality (Average)
    $960,000

Recent comparable sales

Sales selected by similarity to the subject property.

Public appraisal comparison for 2026. Prepared . Appraisal source: Cook County Assessor's Office. Sales data checked in this snapshot: . Showing the last prepared sales evidence while recent sales are refreshed. Matches consider available size, age, location and property characteristics. How comparisons work.

Value history

Up 37.9% in 2026 from 2025.

Assessor market value by tax year, with the change from the previous year listed
Tax yearAssessor market valueChangeChange %
2026$1,040,000+$285,650+37.9%
2025$754,350$00.0%
2024$754,350−$85,650−10.2%
2023$840,000+$245,230+41.2%
2022$594,770−$72,360−10.8%
2021$667,130−$48,120−6.7%
2020$715,250——
6-year total+$324,750+45.4%