Cook County Condo Units, 1999 To 2025, By Township

The Cook County Assessor’s condominium file counts 372,354 condo units in 2025 — 63 fewer than in 2010. Between 1999 and 2010 the count rose every year, by 157,452 units in all, or 73.2 percent, and then it leveled off. Half of that growth sat in buildings put up from 1999 on; the other half, by our reading, was older buildings becoming condominiums.

Residential Condominium Unit Characteristics (3r7i-mrz4), maintained by the Cook County Assessor’s Office, tax years 1999 through 2026 (the 2026 rows not yet final), retrieved September 18, 2026; last updated September 15, 2026 · units are rows the file does not flag as parking, storage or common areas · township names from the assessor’s Parcel Universe (pabr-t5kh) · units are not households

Twelve years of growth, then a plateau

Units are the file’s condominium parcels not flagged as parking, storage or common areas; parking and storage parcels are counted separately. The 2026 rows are not final.
Tax year	Condo units	Parking and storage parcels
1999	214,965	20,830
2000	225,259	24,846
2001	237,220	29,392
2002	249,706	33,531
2003	262,277	38,388
2004	277,772	43,092
2005	293,351	49,424
2006	313,332	57,180
2007	337,181	65,115
2008	356,878	72,084
2009	367,421	78,116
2010	372,417	82,289
2011	374,052	82,869
2012	374,547	83,235
2013	374,321	83,128
2014	374,410	83,278
2015	374,392	83,538
2016	375,191	83,409
2017	375,507	83,466
2018	375,722	83,447
2019	374,764	83,616
2020	374,179	83,957
2021	374,618	84,045
2022	374,350	84,552
2023	372,608	84,809
2024	372,190	84,890
2025	372,354	84,631

The count climbed from 214,965 in 1999 to 372,417 in 2010, gaining in each of those years. Since then it has moved by less than one percent: it peaked at 375,722 in 2018 and stood at 372,354 in 2025, with 372,390 in the 2026 rows so far. The file also carries 84,631 parcels flagged as parking or storage in 2025 and 1,062 common areas, kept out of every unit count here.

New buildings and old ones

Year built is the file’s: for a building converted to condominiums, the year the building went up, not the year it was converted.
Tax year	Units in buildings built before 1999	Units in buildings built 1999 or later	All units
1999	214,965	0	214,965
2010	293,752	78,665	372,417
2018	290,261	85,461	375,722
2025	279,789	92,565	372,354

Split the growth by the age of the building and it divides almost exactly in two. From 1999 to 2010, units in buildings built from 1999 on went from none to 78,665, and units in buildings built before 1999 rose by 78,787. Those older buildings did not go up in those years, so we read the second half as existing buildings becoming condominiums; the file records units, not conversions, so that reading is ours. The plateau since 2010 is two motions canceling out: newer buildings added 13,900 units while units in older buildings fell by 13,963.

Chicago’s townships and the suburbs

The assessor’s township lines, not city or village limits. Chicago’s eight are the townships the assessor’s parcel file assigns to its “City” triad, one of the three groups it reassesses in turn.
Tax year	Chicago’s eight townships	The 30 suburban townships	All of Cook County
1999	98,035	116,930	214,965
2010	215,111	157,306	372,417
2018	219,010	156,712	375,722
2025	218,828	153,526	372,354

Most of the boom was in Chicago’s townships. Their condo units more than doubled from 1999 to 2010, from 98,035 to 215,111; that gain of 117,076 is 74.4 percent of the county’s. By 2025 they held 218,828 units, 58.8 percent of the county’s condos.

The ten townships with the most condo units in 2025.
Township	Units, 1999	Units, 2010	Units, 2025
Lake View (Chicago)	34,771	57,262	57,789
North Chicago (Chicago)	28,615	47,951	47,756
West Chicago (Chicago)	4,898	29,533	33,351
South Chicago (Chicago)	6,063	26,143	27,473
Jefferson (Chicago)	8,723	22,937	23,172
Wheeling	15,157	18,069	17,857
Hyde Park (Chicago)	6,943	15,487	14,267
Schaumburg	12,448	13,741	13,385
Maine	9,077	11,968	11,738
Palatine	8,863	12,418	11,705

Lake View township had the most condos in 1999 and still does, 57,789. West Chicago township grew the most relative to where it started among these ten: from 4,898 units in 1999 to 29,533 in 2010 and 33,351 in 2025, still rising after the county’s count leveled off. South Chicago township went from 6,063 to 27,473. Hyde Park township moved the other way after 2010, from 15,487 units to 14,267.

When the buildings went up

All 372,354 units in the 2025 rows by the year the file records their building as built.
Decade built	Condo units, 2025	Share
Before 1900	7,993	2.1%
1900s	8,805	2.4%
1910s	17,039	4.6%
1920s	24,063	6.5%
1930s	6,633	1.8%
1940s	3,867	1.0%
1950s	11,028	3.0%
1960s	39,218	10.5%
1970s	80,461	21.6%
1980s	45,624	12.3%
1990s	43,978	11.8%
2000s	71,366	19.2%
2010s	7,280	2.0%
2020 to 2025	4,999	1.3%

Buildings from the 1970s hold the most condo units, 80,461, or 21.6 percent, followed by the 2000s with 71,366. Buildings built from 2010 through 2025 hold 12,279, 3.3 percent — sixteen years of new construction, set against the 71,366 of the 2000s’ ten.

What the file confirms, and what it cannot tell you

Confirmed, as recorded: how many condominium parcels the assessor lists each tax year, by township, flag and year built. The file says parking, storage and common-area parcels are challenging to identify and that the assessor is still cleaning those records up, so some parcels counted here as units may be parking or storage, and the reverse; flagged parking and storage parcels rose by 2,342 from 2010 to 2025, and that cleanup could account for part of the decline in older buildings. Not shown: which buildings converted, deconverted or came down, and why; anything about owners or occupants; and whether a unit is lived in. This analysis used only grouped counts, never a parcel number or an address.

Where the record lives

The Residential Condominium Unit Characteristics file and the current-year Parcel Universe, which supplied the township names, sit on Cook County’s data portal. Every figure here was computed from them as retrieved on September 18, 2026.

The bottom line

Cook County’s condo count grew 73.2 percent from 1999 to 2010 and has barely moved since, with new buildings and old ones offsetting each other. Nearly three in five of the county’s condo units now sit in Chicago’s townships.

Three questions the file can answer

How many condo units does Cook County have? 372,354 in the 2025 rows, not counting parking, storage or common areas. Which township has the most? Lake View, 57,789. Which decade’s buildings hold the most units? The 1970s’, with 80,461.

Source: the Cook County Assessor’s Residential Condominium Unit Characteristics file (3r7i-mrz4), tax years 1999 through 2026, retrieved September 18, 2026.
Units: rows not flagged as parking, storage or a common area.
Read: grouped counts by tax year, township, flag and year built; no parcel number, address or owner field selected.
Townships: names from the assessor’s current-year Parcel Universe (pabr-t5kh).
Ours: reading the growth in units in pre-1999 buildings as conversions to condominiums.

Computed by KCM Desk from the Cook County Assessor’s Residential Condominium Unit Characteristics file, retrieved September 18, 2026. Human-guided and edited — about this desk. If you spot an error, corrections come first.