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U.S. Census Bureau · 2025 Population Estimates Program (PEP)

Illinois County Population — 2025 PEP

July 1, 2025 resident population estimates for 102 counties. State total (sum of these county estimates): 12,719,141 persons.

Separate 2025 TIGER/Line county boundaries validate county identity; these are not ACS 2024 survey estimates.

Official Vintage 2025 county identities and unsimplified TIGER coordinates; separate-period ACS housing is joined only by exact full GEOID. Original 2020 counts require separately evidenced compatible geography; incompatible observations remain null with reasons. The revised April estimates base is not an original census count; no boundary allocation is invented.

Source and downloads

2025 Census PEP county estimates, 2020–2025 series; counts are persons, migration counts are persons, published rates are per 1,000, and unavailable values remain null (not zero). 2020 rates are unavailable for the partial-year interval. County totals and characteristics are verified against the pinned raw Census CSV receipts and independent 2025 county geometry.

Official Census PEP county source · Download JSON · Download CSV · Download source metadata

Official state totals and county summaries

Official NST July 1, 2025 state total: 12,719,141 persons (SUMLEV 040, PEP Vintage 2025). County sum: 12,719,141 persons; comparison status: equal.

Official NST July 2020: 12,795,348 persons; July 2020–July 2025 change: -76,207 persons; growth: -0.595584 percent (denominator: official July 2020 population).

County July 2024–July 2025: Growing: 38 · Shrinking: 64 · Unchanged: 0 · Missing: 0. Median county growth: -0.215555 percent.

Largest county: Cook County (GEOID 17031): 5194625 persons.

Fastest county growth: Bond County (GEOID 17005): 2.162651 percent.

Greatest numeric increase: Cook County (GEOID 17031): 5834 persons.

no minimum population; missing excluded per measure; median of county percentages, not population weighted; equal values use ascending full GEOID.

Official state demographics

Resident population · SUMLEV 040 · July 1, 2025 · Census PEP Vintage 2025. Denominator for every share: 12,719,141 resident persons. Six exclusive race groups; Hispanic origin overlaps race and must not be added to it. Release: June 2026; exact day unproved; PEP estimates have no ACS sampling MOE.

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Official state age, sex, race and overlapping Hispanic origin
MeasureCountShare
Female6,479,874 persons50.945846 percent
Male6,239,267 persons49.054154 percent
Ages 18–241,187,061 persons9.332871 percent
Ages 25–443,445,423 persons27.088488 percent
Ages 45–643,088,911 persons24.285532 percent
Ages 65 and older2,379,145 persons18.705233 percent
Under 182,618,601 persons20.587876 percent
American Indian or Alaska Native alone258,148 persons2.029602 percent
Asian alone885,671 persons6.963293 percent
Black or African American alone1,850,169 persons14.546336 percent
Native Hawaiian or other Pacific Islander alone9,929 persons0.078063 percent
Two or more races500,635 persons3.936076 percent
White alone9,214,589 persons72.446630 percent
Hispanic (any race)2,525,697 persons19.857449 percent
Not Hispanic10,193,444 persons80.142551 percent

Official state median age: 39.7 years. Published state SYASEX median age; not a county aggregation, not ACS.

Download all state demographic observations (CSV)

Revised April 1, 2020 estimates base (official NST): 12,821,741 persons; county base sum: 12,821,741 persons; comparison: equal. This is not the original decennial census count.

Original April 1, 2020 Census count: 101 compatible counties; 1 unavailable. Published Census county centers-of-population POPULATION, original 2020 Gazetteer and official 2020–2025 geographic-change evidence; no boundary allocation. Original count, revised April estimates base and July 2020 estimate are separate observations. Documentation: November 2021; exact file release day unproved; retrieval is not release. Official original count source. Original 2020 Gazetteer identity plus Census geographic-change notes 2014–2025; no county-level change recorded from 2020 onward, exact full modern name, and original count required. Any recorded county-level change or referenced counterparty is conservatively unavailable, including unresolved internal redistricting. Same GEOID alone is insufficient. Not a claim of identical cartographic coordinates; no invented allocations.

Source release date unavailable: retained pins do not attest an official release date; retrieval is not release. Reference dates and Vintage 2025 are explicit; no current-vintage refresh is implied.

County population and demographic explorer

Choose a measure, observation year and county without downloading boundaries. Rankings, search, trends and CSV work without a map. Load map explicitly to download the full, unsimplified 2025 TIGER boundaries; this defers rather than removes their payload. The table remains available without JavaScript.

PEP population · persons · July 1, 2025. Denominator: none. Calculation/source: CO POPESTIMATEy. Vintage 2025; null with metric_status reason; measured zero remains zero; no imputation.

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After loading, Tab to a county and press Enter or Space; colors and the legend indicate signed direction and magnitude. Outlines show selection. The county picker works before and after map loading.

Selected county demographic breakdown

July 1, 2025 · Cook County (GEOID 17031). Same-period county population is the share denominator. Hispanic origin overlaps race; do not add origin to race counts. Other overlapping classifications are not additive. Official county median age is from PEP AGESEX MEDIAN_AGE_TOT, not ACS.

County demographics: counts, shares and official median age
Classification / sourceCount or statisticShare / status
Sex · PEP male2,515,607 persons48.427115 percent
Sex · PEP female2,679,018 persons51.572885 percent
Age bands · PEP under181,006,397 persons19.373814 percent
Age bands · PEP age18 24463,649 persons8.925553 percent
Age bands · PEP age25 441,590,138 persons30.611218 percent
Age bands · PEP age45 641,237,752 persons23.827553 percent
Age bands · PEP age65plus896,689 persons17.261862 percent
Race alone (partition) · PEP white alone3,176,862 persons61.156715 percent
Race alone (partition) · PEP black alone1,183,687 persons22.786765 percent
Race alone (partition) · PEP aian alone153,806 persons2.960868 percent
Race alone (partition) · PEP asian alone475,033 persons9.144702 percent
Race alone (partition) · PEP nhpi alone4,243 persons0.081681 percent
Race alone (partition) · PEP two or more200,994 persons3.869269 percent
Hispanic origin (overlaps race) · PEP hispanic any race1,441,908 persons27.757692 percent
Hispanic origin (overlaps race) · PEP not hispanic3,752,717 persons72.242308 percent
Other overlapping classifications (not additive) · PEP white alone or combination3,358,948 persons64.661992 percent
Other overlapping classifications (not additive) · PEP not hispanic white alone2,044,609 persons39.360089 percent
Official county median age · AGESEX MEDIAN_AGE_TOT38.4 yearsNot a share; not ACS or an average of county medians

Use Ctrl/Command or Shift to select multiple counties. The following trend uses exact resident persons, not percentages; county size affects the scale. Missing observations break lines; the revised April estimates base is a separate dashed partial interval.

2025 county population rankings

All 102 county estimates are present without JavaScript, ranked by 2025 population (largest first). Signed changes compare July 1, 2024 to July 1, 2025. Unavailable is not zero; equal values break ties by GEOID (ascending).

Showing all 102 counties; ranked by 2025 population, descending.

Illinois County Population — 2025 PEP — July 1, 2025; rank reflects the selected ordering
RankCountyGEOIDPopulation (persons)Signed change (persons)Signed change (percent)
1Cook County170315,194,625+5834 persons+0.112435%
2DuPage County17043934,298+1647 persons+0.176593%
3Lake County17097719,339+849 persons+0.118164%
4Will County17197712,253+3273 persons+0.461649%
5Kane County17089525,757+2327 persons+0.444568%
6McHenry County17111317,751+2021 persons+0.640104%
7Winnebago County17201283,674+709 persons+0.250561%
8Madison County17119263,110-207 persons-0.078612%
9St. Clair County17163250,708-667 persons-0.265341%
10Champaign County17019209,972+794 persons+0.379581%
11Sangamon County17167194,170+134 persons+0.069059%
12Peoria County17143178,553+12 persons+0.006721%
13McLean County17113171,419-93 persons-0.054224%
14Kendall County17093145,470+2345 persons+1.638428%
15Rock Island County17161141,869+278 persons+0.196340%
16Tazewell County17179130,049+67 persons+0.051546%
17LaSalle County17099107,773-102 persons-0.094554%
18Kankakee County17091105,525-289 persons-0.273121%
19DeKalb County17037101,835+1214 persons+1.206508%
20Macon County1711599,300-649 persons-0.649331%
21Vermilion County1718371,259-197 persons-0.275694%
22Williamson County1719967,225+151 persons+0.225124%
23Adams County1700164,267+51 persons+0.079419%
24Whiteside County1719554,121-302 persons-0.554912%
25Grundy County1706354,052+331 persons+0.616146%
26Boone County1700753,568+42 persons+0.078467%
27Jackson County1707752,501-181 persons-0.343571%
28Ogle County1714151,399+125 persons+0.243788%
29Henry County1707348,095-98 persons-0.203349%
30Knox County1709547,767-197 persons-0.410725%
31Coles County1702946,607+34 persons+0.073004%
32Macoupin County1711743,748-169 persons-0.384817%
33Stephenson County1717743,220-202 persons-0.465202%
34Woodford County1720338,111-87 persons-0.227761%
35Clinton County1702737,128+40 persons+0.107852%
36Franklin County1705536,916-38 persons-0.102831%
37Marion County1712136,382-119 persons-0.326018%
38Jefferson County1708136,147+35 persons+0.096921%
39Livingston County1710535,057-127 persons-0.360960%
40Monroe County1713334,840-265 persons-0.754878%
41Effingham County1704934,519-22 persons-0.063692%
42Christian County1702133,443+1 persons+0.002990%
43Lee County1710332,914+63 persons+0.191775%
44Fulton County1705732,901+94 persons+0.286524%
45Morgan County1713732,515-124 persons-0.379914%
46Bureau County1701132,510-9 persons-0.027676%
47Randolph County1715729,921+51 persons+0.170740%
48Montgomery County1713528,076+239 persons+0.858570%
49Logan County1710727,182-37 persons-0.135934%
50Iroquois County1707526,150-72 persons-0.274579%
51McDonough County1710925,916-199 persons-0.762014%
52Saline County1716522,772-58 persons-0.254052%
53Jo Daviess County1708521,594-62 persons-0.286295%
54Jersey County1708321,160+5 persons+0.023635%
55Fayette County1705120,790-164 persons-0.782667%
56Shelby County1717320,576+22 persons+0.107035%
57Perry County1714520,160-216 persons-1.060071%
58Douglas County1704119,880+32 persons+0.161225%
59Crawford County1703318,648+27 persons+0.144998%
60Bond County1700516,959+359 persons+2.162651%
61Hancock County1706716,803-133 persons-0.785309%
62Piatt County1714716,791+149 persons+0.895325%
63Union County1718116,656-176 persons-1.045627%
64Edgar County1704516,323-59 persons-0.360151%
65Warren County1718716,222+106 persons+0.657731%
66Wayne County1719115,882-1 persons-0.006296%
67Carroll County1701515,419-49 persons-0.316783%
68Mercer County1713115,229-63 persons-0.411980%
69Richland County1715915,219-149 persons-0.969547%
70De Witt County1703915,118-126 persons-0.826555%
71Clark County1702315,114-27 persons-0.178324%
72Moultrie County1713914,371-71 persons-0.491622%
73Pike County1714914,231-55 persons-0.384992%
74Lawrence County1710113,790+23 persons+0.167066%
75Washington County1718913,564-15 persons-0.110465%
76Massac County1712713,502-114 persons-0.837250%
77Johnson County1708713,363+16 persons+0.119877%
78White County1719313,250-199 persons-1.479664%
79Ford County1705313,216-110 persons-0.825454%
80Clay County1702512,793-52 persons-0.404827%
81Cass County1701712,463-67 persons-0.534717%
82Mason County1712512,411-78 persons-0.624550%
83Menard County1712911,863-61 persons-0.511573%
84Marshall County1712311,473-98 persons-0.846945%
85Greene County1706111,313-80 persons-0.702186%
86Wabash County1718510,907-119 persons-1.079267%
87Cumberland County1703510,208-70 persons-0.681066%
88Jasper County170799,032-17 persons-0.187866%
89Hamilton County170657,859-2 persons-0.025442%
90Schuyler County171696,657-66 persons-0.981705%
91Brown County170096,401-37 persons-0.574713%
92Henderson County170715,984-47 persons-0.779307%
93Edwards County170475,898-89 persons-1.486554%
94Putnam County171555,619+2 persons+0.035606%
95Stark County171755,319+50 persons+0.948947%
96Scott County171714,866-23 persons-0.470444%
97Pulaski County171534,820-63 persons-1.290190%
98Gallatin County170594,616-67 persons-1.430707%
99Alexander County170034,570-41 persons-0.889178%
100Calhoun County170134,300-10 persons-0.232019%
101Pope County171513,672-45 persons-1.210654%
102Hardin County170693,588-13 persons-0.361011%

County population trend · 2020–2025

Resident population (persons), not ACS housing. April 1, 2020 estimates base is distinct from the July 1, 2020 estimate. The April–July 2020 change is partial-year; the July 2020–July 2021 interval is the first July-to-July comparison. No 2020 annual rate is shown. Missing observations are unavailable, never zero.

Showing Cook County (GEOID 17031). Select a county on the map or in the rankings table to update this trend.

Horizontal axis: year (2020–2025); vertical axis: resident population (persons). The 2020 base is a separate April 1 observation; July 1 estimates run from 2020 through 2025. Focus the chart viewport and use Left/Right arrows to scroll on narrow screens. Complete axis labels stay here outside the scrolling chart; the table gives exact values and availability.

Population observations for Cook County (GEOID 17031), persons
DatePopulation (persons)Interval
April 1, 2020 base5,279,010Estimates base; not July 1
July 1, 20205,263,651April–July partial-year; no annual rate
July 1, 20215,186,249July 2020–July 2021 comparison
July 1, 20225,127,866July-to-July estimate
July 1, 20235,142,853July-to-July estimate
July 1, 20245,188,791July-to-July estimate
July 1, 20255,194,625July-to-July estimate

County population and median home value · different vintages

Each point pairs a county’s PEP July 1, 2025 resident population (persons) with its ACS 2024 5-year median owner-occupied home value (B25077, U.S. dollars). These are different reference periods and different statistical programs. This descriptive comparison does not imply causality or matched vintages. Suppressed, missing or invalid ACS estimates are unavailable, not zero and not plotted. A valid zero remains zero.

The exact-value table below works without JavaScript; chart loading requires JavaScript.

Select a county using the map or rankings to coordinate the comparison.

County comparison: PEP July 1, 2025 population (persons) and ACS 2024 5-year median owner-occupied home value (U.S. dollars); unavailable values identified
CountyGEOIDPEP July 1, 2025 population (persons)ACS 2024 5-year median home value (U.S. dollars)
Adams County1700164,267$162,600
Alexander County170034,570$59,800
Bond County1700516,959$145,700
Boone County1700753,568$216,900
Brown County170096,401$150,300
Bureau County1701132,510$126,900
Calhoun County170134,300$190,900
Carroll County1701515,419$114,500
Cass County1701712,463$97,100
Champaign County17019209,972$211,500
Christian County1702133,443$115,500
Clark County1702315,114$132,400
Clay County1702512,793$97,400
Clinton County1702737,128$192,400
Coles County1702946,607$127,400
Cook County170315,194,625$324,500
Crawford County1703318,648$121,100
Cumberland County1703510,208$126,000
DeKalb County17037101,835$243,600
De Witt County1703915,118$130,300
Douglas County1704119,880$150,400
DuPage County17043934,298$391,400
Edgar County1704516,323$97,300
Edwards County170475,898$100,000
Effingham County1704934,519$189,500
Fayette County1705120,790$130,700
Ford County1705313,216$122,000
Franklin County1705536,916$89,000
Fulton County1705732,901$107,200
Gallatin County170594,616$82,900
Greene County1706111,313$95,200
Grundy County1706354,052$271,700
Hamilton County170657,859$113,700
Hancock County1706716,803$113,800
Hardin County170693,588$103,800
Henderson County170715,984$104,400
Henry County1707348,095$151,600
Iroquois County1707526,150$137,800
Jackson County1707752,501$137,300
Jasper County170799,032$125,500
Jefferson County1708136,147$126,000
Jersey County1708321,160$171,900
Jo Daviess County1708521,594$209,900
Johnson County1708713,363$160,500
Kane County17089525,757$327,000
Kankakee County17091105,525$192,600
Kendall County17093145,470$322,400
Knox County1709547,767$111,900
Lake County17097719,339$345,700
LaSalle County17099107,773$161,900
Lawrence County1710113,790$99,100
Lee County1710332,914$154,600
Livingston County1710535,057$142,200
Logan County1710727,182$134,400
McDonough County1710925,916$107,500
McHenry County17111317,751$308,100
McLean County17113171,419$208,400
Macon County1711599,300$127,300
Macoupin County1711743,748$138,200
Madison County17119263,110$173,000
Marion County1712136,382$103,000
Marshall County1712311,473$142,800
Mason County1712512,411$103,400
Massac County1712713,502$121,900
Menard County1712911,863$185,500
Mercer County1713115,229$146,700
Monroe County1713334,840$282,100
Montgomery County1713528,076$112,300
Morgan County1713732,515$130,800
Moultrie County1713914,371$134,000
Ogle County1714151,399$189,200
Peoria County17143178,553$158,500
Perry County1714520,160$112,600
Piatt County1714716,791$180,600
Pike County1714914,231$101,400
Pope County171513,672$143,800
Pulaski County171534,820$85,100
Putnam County171555,619$172,700
Randolph County1715729,921$135,100
Richland County1715915,219$112,000
Rock Island County17161141,869$150,400
St. Clair County17163250,708$180,300
Saline County1716522,772$94,300
Sangamon County17167194,170$176,300
Schuyler County171696,657$109,700
Scott County171714,866$96,400
Shelby County1717320,576$137,100
Stark County171755,319$104,500
Stephenson County1717743,220$134,900
Tazewell County17179130,049$167,500
Union County1718116,656$131,700
Vermilion County1718371,259$97,200
Wabash County1718510,907$104,900
Warren County1718716,222$105,000
Washington County1718913,564$155,700
Wayne County1719115,882$110,700
White County1719313,250$108,100
Whiteside County1719554,121$127,100
Will County17197712,253$319,600
Williamson County1719967,225$156,400
Winnebago County17201283,674$164,500
Woodford County1720338,111$197,600