🚀 Cook County Assessor Property Scraper

Access comprehensive property assessment data for Cook County, Illinois, the second-largest county in the United States. This tool provides instant access to official property records, assessed values, ownership information, physical characteristics, sales history, and Board of Review appeals for over 1.8 million properties across Chicago and 130 surrounding municipalities.

Whether you're a real estate investor analyzing property values, a researcher studying housing trends, a business analyst conducting market research, or a homeowner researching your neighborhood, this tool delivers authoritative Cook County property data in a format you can use immediately. No technical skills required, no complicated setup, just accurate property data pulled directly from the Cook County Open Data Portal.

Perfect for real estate professionals, appraisers, market researchers, tax consultants, attorneys, journalists, and anyone who needs reliable Cook County property information without manual data entry or web browsing.

✨ What Does It Do

This tool collects detailed property assessment data from Cook County, Illinois, including:

• 14-digit Property Index Number (PIN) - The unique identifier for every property in Cook County, essential for official records and tax lookup
• Complete Property Address - Street address, apartment/unit number, city, and ZIP code for accurate property identification
• Owner Mailing Information - Mailing address, city, state, and ZIP for property owners, useful for direct outreach and verification
• Location Data - Precise latitude and longitude coordinates for mapping, spatial analysis, and geographic research
• Administrative Boundaries - Township name and code, municipality, ward, commissioner district, and school districts for demographic studies
• Assessed & Market Values - Current certified assessed value and estimated market value (calculated per Illinois law as assessed value × 3)
• Property Classification - Official Cook County property class codes that determine tax rates and assessment methods
• Physical Characteristics - Year built, building square footage, land square footage, bedrooms, bathrooms, construction quality, exterior materials, heating/cooling systems, basement, garage size, and more
• Historic Assessed Values - Year-by-year assessment history including mailed, certified, and Board of Review values for land, building, and total
• Sales History - Complete transaction records with sale dates, prices, document numbers, deed types, buyer names, and seller names
• Appeals History - Board of Review appeal records showing appeal type, assessor values, BOR values, results, change reasons, and attorney information
• Environmental & Special Zones - O'Hare airport noise zone designation, floodplain status, and First Street flood factor ratings (1-10)
• Direct Property Link - URL to the official Cook County Assessor property detail page for verification

All data is sourced from the Cook County Open Data Portal, ensuring accuracy and official status for professional use.

🎬 Demo Video

Demo video coming soon.

🔧 Input

Configure your property search with these flexible options:

Search Mode

Use one approach per run:

• Start URLs (startUrls) - Provide an array of direct property URLs or PINs.
• Search filters - Use one filter mode below only when startUrls is empty.

Choose how you want to find properties with filters:

• By PIN - Look up specific properties using their 14-digit Property Index Numbers (most precise method)
• By Address - Search by street name or partial address (e.g., "MICHIGAN AVE", "JANSSEN")
• By Township - Retrieve all properties within a Cook County township (e.g., Evanston, Lake View, New Trier)
• By Municipality - Get all properties in a city or village (e.g., Chicago, Oak Park, Skokie)

Search Parameters

PINs - Enter one or more 14-digit Property Index Numbers when using PIN search mode. Example: 14321090140000

Street Address - Enter a street name or partial address when using address search. Use uppercase for best results (e.g., "MICHIGAN AVE", "LAKE SHORE DRIVE"). Partial matches are supported.

City - Optional city filter to narrow address searches (e.g., "CHICAGO", "OAK PARK", "EVANSTON"). Leave blank to search all cities.

Township - Select a Cook County township when using township search mode. Options include all 38 Cook County townships from Barrington to Worth.

Municipality - Enter a city or village name when using municipality search mode (e.g., "Chicago", "Evanston", "Oak Park").

Data Options

Assessment Year - Optionally filter data to a specific year (1999-2026). Leave blank to get the most recent available data.

Include Assessed Values History - Toggle to include year-by-year assessment history with mailed, certified, and Board of Review values (default: enabled).

Include Property Characteristics - Toggle to include physical details like bedrooms, bathrooms, construction quality, square footage, and building features (default: enabled).

Include Sales History - Toggle to include complete transaction records with prices, dates, and parties (default: disabled).

Include Board of Review Appeals - Toggle to include appeal history with assessor/BOR values and outcomes (default: disabled).

Max Properties (maxItems) - Limit the number of properties returned.
Free users are capped at 100 items per run. Paid users can request higher limits.

Example Input

{
  "searchMode": "pin",
  "pins": ["14321090140000", "20144090260000"],
  "includeAssessedValues": true,
  "includeCharacteristics": true,
  "includeSales": false,
  "includeAppeals": false,
  "maxItems": 100
}

Or search by address:

{
  "searchMode": "address",
  "address": "MICHIGAN AVE",
  "city": "CHICAGO",
  "includeAssessedValues": true,
  "includeCharacteristics": true,
  "maxItems": 50
}

Or retrieve all properties in a township:

{
  "searchMode": "township",
  "township": "Lake View",
  "includeAssessedValues": true,
  "includeCharacteristics": false,
  "maxItems": 500
}

📊 Output

The tool returns detailed property records in JSON format. Here's what a typical property record looks like:

{
  "pin": "14321090140000",
  "property_address": "2548 N JANSSEN AVE",
  "property_apt_no": null,
  "property_city": "CHICAGO",
  "property_zip": "60614",
  "mailing_address": "2548 N JANSSEN AVE",
  "mailing_city": "CHICAGO",
  "mailing_state": "IL",
  "mailing_zip": "60614",
  "latitude": 41.92763,
  "longitude": -87.64382,
  "township_code": "71",
  "township_name": "Lake View",
  "neighborhood": "064",
  "municipality": "Chicago",
  "ward": "43",
  "commissioner_dist": "2",
  "school_elem_district": "Chicago Public Schools District 299",
  "school_hs_district": "Chicago Public Schools District 299",
  "ohare_noise": false,
  "floodplain": false,
  "fs_flood_factor": 2,
  "property_class": "211",
  "assessed_value": 28420,
  "market_value": 85260,
  "year_built": 1906,
  "building_sq_ft": 2856,
  "land_sq_ft": 3125,
  "assessed_values": [
    {
      "year": "2024",
      "class": "211",
      "mailed_building": 24362,
      "mailed_land": 4058,
      "mailed_total": 28420,
      "certified_building": 24362,
      "certified_land": 4058,
      "certified_total": 28420,
      "board_building": null,
      "board_land": null,
      "board_total": null
    }
  ],
  "characteristics": {
    "type": "residential",
    "year": "2024",
    "year_built": 1906,
    "building_sq_ft": 2856,
    "land_sq_ft": 3125,
    "bedrooms": 3,
    "rooms": 7,
    "full_baths": 2,
    "half_baths": 1,
    "fireplaces": 1,
    "residence_type": "Two Story",
    "construction_quality": "Average",
    "exterior_wall": "Frame",
    "heat": "Forced Air",
    "air_conditioning": "Central",
    "basement": "Full",
    "roof_construction": "Asphalt Shingle",
    "use": "Single Family",
    "garage_size": "2 Car"
  },
  "sales": null,
  "appeals": null,
  "url": "https://www.cookcountyassessor.com/pin/14321090140000",
  "scrapedAt": "2026-02-19T04:35:22.118Z"
}

What Each Field Means

• pin - The unique 14-digit Property Index Number used by Cook County for all official records
• property_address - The street address where the property is located
• property_city - The city where the property is physically located
• property_zip - The ZIP code for the property's physical address
• mailing_address - Where tax bills and official notices are sent (may differ from property address)
• latitude/longitude - GPS coordinates for mapping and location-based analysis
• township_name - The Cook County township that contains the property (determines assessment cycle)
• municipality - The city or village that governs the property (determines local tax rates)
• assessed_value - The official assessed value used to calculate property taxes
• market_value - Estimated market value (assessed value × 3, per Illinois property tax law)
• year_built - Construction year of the building
• building_sq_ft - Total square footage of the building structure
• land_sq_ft - Total square footage of the land parcel
• property_class - Official classification code (211 = single-family home, 299 = multi-unit, etc.)
• characteristics - Detailed physical features including bedrooms, bathrooms, construction materials, heating/cooling, and more
• assessed_values - Year-by-year history showing how assessments have changed over time
• sales - Transaction history with prices, dates, and parties (when enabled)
• appeals - Board of Review appeal records (when enabled)

Export Options

Download your data in multiple formats:

• JSON - Perfect for developers and data analysis tools
• CSV - Open in Excel or any spreadsheet application
• Excel (XLSX) - Native Excel format with proper formatting

💎 Why Choose the Cook County Assessor Property Scraper?

Official, Authoritative Data - Unlike third-party real estate sites, this tool pulls directly from the Cook County Open Data Portal, giving you the same data used by the assessor's office, tax collectors, and government agencies. No guesswork, no outdated information.

Comprehensive Property Intelligence - Get everything about a property in one query: current and historic assessments, physical characteristics, sales history, appeals, environmental designations, and administrative boundaries. No need to piece together information from multiple sources.

Flexible Search Options - Whether you have a specific PIN, want to research a neighborhood by address, or need every property in a township or municipality, this tool adapts to your workflow. Perfect for both targeted research and bulk data collection.

No Technical Skills Required - Simple point-and-click interface. Enter your search criteria, click run, and download results. No coding, no command-line tools, no complicated configuration.

Built for Professionals - Designed for real estate investors, appraisers, researchers, attorneys, and analysts who need reliable data fast. Export to Excel or CSV for immediate use in your existing workflows.

Cost-Effective & Fast - The Cook County Open Data Portal is free and unrestricted. No rate limits, no authentication required. Get thousands of property records in minutes, not hours.

📋 How to Use

Get started in minutes with these simple steps:

1. Sign Up - Create a free account w/ $5 credit on the Apify platform. No credit card required to start.

2. Find the Actor - Search for "Cook County Assessor Property Scraper" in the Apify Store, or access it directly from your dashboard.

3. Configure Your Search - Choose your search mode (PIN, address, township, or municipality), enter your search criteria, and select which data options to include (assessed values, characteristics, sales, appeals).

4. Run the Tool - Click "Start" and the tool will immediately begin collecting property data from the Cook County Open Data Portal.

5. Download Your Data - Once complete, export your results in JSON, CSV, or Excel format. Use the data in your spreadsheets, databases, or analysis tools.

No Technical Skills Required - The entire process is point-and-click. If you can use a web form, you can use this tool.

Pro Tip: For large searches (entire townships or municipalities), start with a smaller maxItems limit to test your query, then expand once you've confirmed the results match your needs.

🎯 Business Use Cases

Real Estate Investors & Developers

• Property Acquisition Research - Look up assessed values, sales history, and physical characteristics for potential investment properties before making offers
• Market Value Analysis - Compare assessed values and market values across neighborhoods to identify undervalued properties or emerging markets
• Portfolio Management - Track assessment changes for owned properties to anticipate tax increases and budget accordingly
• Bulk Property Analysis - Download all properties in a target township or municipality to identify acquisition opportunities at scale

Real Estate Appraisers & Assessors

• Comparable Sales Research - Pull sales history and property characteristics for comparable properties to support valuation reports
• Assessment Verification - Verify official assessed values and property classifications for client properties
• Market Trend Analysis - Analyze year-over-year assessment changes across neighborhoods to identify market trends and support valuation conclusions
• Physical Characteristics Confirmation - Access detailed building features (square footage, bedrooms, construction quality) to ensure appraisal accuracy

Tax Consultants & Property Tax Attorneys

• Appeal Preparation - Review assessment history and Board of Review appeal outcomes to build stronger tax appeal cases
• Client Property Research - Quickly look up current and historic assessments for client properties to identify potential over-assessments
• Comparable Property Analysis - Find similar properties with lower assessments to support tax reduction arguments
• Township Assessment Trends - Track assessment patterns across townships to identify systematic over-assessment issues

Market Researchers & Data Analysts

• Housing Market Studies - Analyze property characteristics, values, and sales across municipalities to study housing affordability and market dynamics
• Demographic Research - Map properties by school district, ward, or commissioner district for demographic and policy research
• Environmental Analysis - Identify properties in floodplains or noise zones to study environmental impact on property values
• Historic Trend Analysis - Track how assessed values have changed over decades to study neighborhood evolution and gentrification patterns

Journalists & Public Interest Researchers

• Property Ownership Investigations - Look up owner mailing addresses to identify absentee ownership patterns or institutional investors
• Tax Assessment Equity Studies - Compare assessments across neighborhoods to investigate potential racial or economic disparities in property taxation
• Public Records Reporting - Access authoritative government data for stories about real estate, taxation, or local development
• Appeal Pattern Analysis - Analyze Board of Review appeal outcomes to investigate whether certain attorneys or property types receive preferential treatment

❓ FAQ

How does this tool work?

This tool connects directly to the Cook County Open Data Portal, the official source for all Cook County property assessment data. Simply enter your search criteria (PIN, address, township, or municipality), and the tool retrieves property records in seconds. No complex setup, no technical knowledge required. The data comes straight from the same system used by the Cook County Assessor's office.

How accurate and current is the data?

The data is as accurate and current as the official Cook County records. We pull directly from the Cook County Open Data Portal (datacatalog.cookcountyil.gov), which is maintained by Cook County government. Assessment data is typically updated after each triennial reassessment cycle and Board of Review decisions. Sales and appeals data are updated regularly as new transactions and decisions are recorded. You're getting the same data used by county officials, appraisers, and tax collectors.

Can I search for properties without knowing the PIN?

Absolutely. While PIN search is the most precise method, you can also search by street address (even partial addresses like "MICHIGAN AVE"), by township (to get all properties in Lake View, Evanston, etc.), or by municipality (to get all properties in Chicago, Oak Park, Skokie, etc.). The address search is especially useful when you know the general location but not the exact PIN.

What's the difference between assessed value and market value?

Assessed value is the official value assigned by the Cook County Assessor's office and used to calculate property taxes. Market value is an estimate of what the property would sell for. Under Illinois law, assessed value for residential property is approximately one-third of market value, so this tool calculates estimated market value as assessed value × 3. For example, if a property has an assessed value of $30,000, the estimated market value is $90,000.

Can I download data for an entire township or city?

Yes. Select "By Township" or "By Municipality" as your search mode, choose your target area, and the tool will retrieve all properties in that area. For very large municipalities like Chicago (which has over 1 million properties), you may want to set a maxItems limit or search by smaller geographic units like specific townships or addresses. The tool is designed to handle bulk data collection efficiently.

Can I schedule this to run automatically?

Yes. Apify supports scheduled runs so you can automatically refresh your property data daily, weekly, or monthly. This is perfect for monitoring assessment changes, tracking new sales, or maintaining up-to-date property databases. Set it once and let the tool keep your data current.

What if I need help or have questions?

We're here to help. Check this FAQ first for common questions. If you need additional support, visit the Apify support page or contact us directly through the contact form at the bottom of this page. For custom data projects or bulk data needs, we can work with you to create a tailored solution.

🔗 Integrate Cook County Assessor Property Scraper with any app

Connect this actor with your favorite tools:

• Make - Automate workflows
• Zapier - Connect 5000+ apps
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• Airbyte - Data pipelines
• Google Drive - Export to spreadsheets

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🆘 Need Help?

Have questions? Check the FAQ section above for answers to common questions about using this tool.

Need technical support? Visit the Apify support page for documentation, tutorials, and troubleshooting guides.

Custom data projects? If you need a custom solution, bulk data extraction, or specialized data processing, contact us. We work with businesses and researchers to create tailored data collection solutions.

📞 Contact

Contact us to request a new scraper, propose a custom data project, or report a technical issue with this actor at https://tally.so/r/BzdKgA

⚠️ Disclaimer

This Actor is an independent tool and is not affiliated with, endorsed by, or sponsored by Cook County, the Cook County Assessor's Office, or any of its subsidiaries. All trademarks mentioned are the property of their respective owners. This tool accesses publicly available data from the Cook County Open Data Portal.