Cook County Value

12315 Thornberry Dr Lemont, IL 60439

5 bed / 4 bath, 4,304 sqft, built 2017, in Lemont. Assessor market value for 2026: $1,120,000.

Cook County account 22303070090000

Assessor market value
$1,120,000
Tax year 2026 · before exemptions; the assessed value on your notice is 10% of it
Living area
4,304 sqft
$260 per sqft
Year built
2017
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 59.7% from $701,300 in 2025 to $1,120,000 in 2026.
  • Assessor market value per square footThe current public record shows about $260 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

Showing 5 of the 8 similar homes in this property's equity comparison, from public appraisal records.

  • 12428 Province Dr Lemont, IL 60439
    4,253 sqft | $252/sqft | built 2018 | Similar size (4,253 vs 4,304 sqft); Similar age (2018 vs 2017); Similar lot size (12,807 vs 12,263 sqft)
    $1,070,000
  • 12474 Thornberry Dr Lemont, IL 60439
    4,332 sqft | $231/sqft | built 2006 | Similar size (4,332 vs 4,304 sqft); Similar lot size (12,245 vs 12,263 sqft); Same quality (Average)
    $1,000,000
  • 13631 Cambridge Dr Lemont, IL 60439
    4,497 sqft | $238/sqft | built 2016 | Similar size (4,497 vs 4,304 sqft); Similar age (2016 vs 2017); Similar lot size (13,035 vs 12,263 sqft)
    $1,070,000
  • 12445 Thornberry Dr Lemont, IL 60439
    4,273 sqft | $225/sqft | built 2008 | Similar size (4,273 vs 4,304 sqft); Similar lot size (12,274 vs 12,263 sqft); Same quality (Average)
    $960,000
  • 12620 Briarcliffe Dr Lemont, IL 60439
    4,527 sqft | $245/sqft | built 2017 | 5% larger (4,527 vs 4,304 sqft); Built same year (2017); Similar lot size (13,005 vs 12,263 sqft)
    $1,110,000

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: . Matches consider available size, age, location and property characteristics. How comparisons work.

Value history

Up 59.7% in 2026 from 2025.

Assessor market value by tax year, with the change from the previous year listed
Tax yearAssessor market valueChangeChange %
2026$1,120,000+$418,700+59.7%
2025$701,300$00.0%
2024$701,300−$126,530−15.3%
2023$827,830+$178,050+27.4%
2022$649,780$00.0%
2021$649,780−$54,070−7.7%
2020$703,850——
6-year total+$416,150+59.1%