Build an Absentee Owner Mailing List for a ZIP Code

Say you buy two- to four-flats on Chicago’s southwest side and you want to write to every landlord in ZIP 60629 (Chicago Lawn) who does not live in the building. A letter to the property reaches a tenant, so what you need is each owner’s own mailing address, plus enough about the building to decide whether the letter is worth a stamp. Cook County publishes all of it. It just publishes it in pieces.

The manual way, and what it costs

The free route is better than most counties offer. Cook’s Parcel Addresses dataset exports to CSV, and it carries both the property address and the tax-bill mailing address, so if you are at home in a spreadsheet you can download it, filter to 60629 and compare the two columns yourself. For a one-off list, do that.

Three things make it slower than it looks. The file is countywide, 1,863,562 parcels for 2026, before you filter to one ZIP. Values, building details and sales sit in three other datasets you join on the 14-digit PIN, and the Assessor had not published the City of Chicago’s 2026 values by 29 September 2026, so a join on this year alone comes back empty for every Chicago parcel. And the dataset has two name columns: the one labelled owner matched the buyer of a sale since 2023 on 3 of 250 parcels checked, while the taxpayer name matched on 201.

The faster way

US Property Records Export & Owner Lookup (County Assessor) does the same search once and hands back every row at once.

{
  "areas": ["60629"],
  "preset": "absentee_owners",
  "maxResultsPerArea": 100
}

areas: ["60629"] becomes Cook County plus a ZIP filter. The absentee_owners preset keeps owners whose mailing address is another state, another city or another street, and drops government owners, since a city agency is not a lead. maxResultsPerArea: 100 is a first look at $2.00. Run it with countOnly first and it tells you, free, that 60629 has 25,087 parcels. With the cap removed, the run behind this article returned all 5,345 absentee parcels in 316 seconds, which at $0.02 a row is $106.90.

What comes back

A real row from that run:

{
  "query": "60629",
  "query_type": "export",
  "county": "Cook",
  "parcel_id": "19153090030000",
  "situs_address": "6007 S KEATING AVE",
  "situs_zip": "60629",
  "owner_name": "ILLIANA PROPERTY MGMT",
  "owner_type": "company",
  "mailing_address": "940 PERTHSHIRE LANE",
  "mailing_city": "DYER",
  "mailing_state": "IN",
  "mailing_zip": "46311",
  "absentee_tier": "out_of_state",
  "absentee_basis": "mails to IN",
  "assessed_value": 38000,
  "property_class_desc": "Multi-Family",
  "year_built": 1910,
  "building_sqft": 2957,
  "bedrooms": 6,
  "last_sale_date": "2012-08-01",
  "last_sale_price": 155000,
  "source": "Cook County Assessor (open data)"
}

Field	What it told us across the 5,345 rows
absentee_tier	324 owners mail from another state, 1,498 from another city, 3,523 from another Chicago address
owner_type	4,322 individuals, 923 companies, 100 trusts
property_class_desc	3,199 single-family or multi-family buildings; the rest other residential, commercial, 7+ unit buildings or vacant land
owner_name	248 owners hold 3 or more parcels in the ZIP, 1,250 parcels between them
last_sale_date	428 of the 4,139 rows with a sale date changed hands in 2024 or later

absentee_tier is the column that turns a parcel list into a mailing list, because it decides where the letter goes. Most of the 1,498 out_of_city owners live a suburb away (171 in Oak Lawn, 113 in Burbank), and the 324 out_of_state owners are spread widest, with 56 mailing from California, 40 from Texas and 28 from Florida.

What you’d do with it

Filter to Multi-Family, sort by owner_name to spot the 248 multi-parcel owners, and send each of them one letter rather than several. Export to CSV and mail-merge from owner_name and the four mailing columns. Next quarter, rerun the same input with soldAfter set to the day you last ran it, and you get only the parcels that changed hands since, which are the new owners worth a letter.

Worth knowing

The absentee tier is worked out from the county’s own address text, so an owner who uses a PO box in the same city reads as same_city_diff_address, not as owner-occupied; check before you treat the 3,523 as landlords. Cook publishes assessed value, not market value (for a house it is 10% of the Assessor’s market value), and the values here are the 2025 roll because 2026 was not out for Chicago yet. Owner type comes from the name, so a church or a trust with an unusual name can land in the wrong bucket, and nothing here includes phone numbers or email.

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Run it yourself: How to run US Property Records Export & Owner Lookup (County Assessor) walks the whole thing step by step.

If you start from a list of addresses rather than an area, Look up who owns a list of property addresses is the other way in. For listing-side data on the same buildings, such as photos and listing history, use Zillow & Redfin Property Data Scraper.