ZIP Codes of Lake County, IN

Population & People
Population & People
Total Population
504,725
Household Income
Household Income
Median Income
$65,872
Housing
Housing
Total Housing Units
218,877
Business & Economy
Business & Economy
Total Businesses
10,597
Employment
Employment
Employment Rate
57.34%
Education
Education
Bachelor's Degree+
25.82%
Source: U.S. Census ACS 2024 5-Year Estimates · rolled up across the 32 ZIPs in this county.
Data Last Updated: June 1, 2026
ZIP Codes:32 ZIP Codes (25 Standard, 7 PO Box, 0 Unique) [See All]
Area Code:219
Timezone:Central (GMT -06:00)
Local Time:2:12:07 PM
Population:504,725 [See All]
FIPS:18089
CBSA:Chicago-Naperville-Elgin, IL-IN
Land Area:471 sq mi
Water Area:17 sq mi
Coordinates:41.5084, -87.3995
Quick Link:
https://www.zip-codes.com/county/in-lake.asp
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Top 3 most populous in Indiana
#2 of 92 counties in Indiana, with 504,725 residents.
Sharp income gradient
Wealthiest ZIP earns 4.5× the poorest — $127,146 vs $28,526.
Among Indiana's 5 densest counties
1,071 people per square mile (#2 statewide).
Striking education divide
Bachelor's share spans 7.8% to 49.9% — a 42-point gap.

Standout ZIPs in this County


Most Populous
Crown Point · 71,673 people
14.2% of county total
Highest Income
Saint John · $127,146 median
1.9× county average
Largest Land Area
Lowell · 113.9 sq mi
Spans the most ground
Fastest Growth
Saint John · 33.7% (10-yr)
14,092 → 18,843 residents
Most Educated
Munster · 49.9% bachelor's+
8,578 of 17,196 adults 25+

Things worth knowing about Lake County


504,725 residents live across 32 ZIPs covering 471 sq mi, served by 19 distinct USPS-recognized cities.

Population moved from 496,372 to 504,725 from 2014 to 2024 — a +1.7% change. 11 ZIPs gained residents, 16 lost.

The county's wealthiest ZIP 46373 (Saint John, $127,146 median) and poorest ZIP 46407 (Gary, $28,526) are 11.5 miles apart — a 4.5× income gap across local geography.

Median home values vary 6.8× across this county — from $60,200 in 46407 (Gary) to $408,900 in 46373 (Saint John).

Density varies 28× across the county — from 173 people/sq mi in 46356 (Lowell) to 4,812 in 46324 (Hammond).

Educational attainment ranges from 7.8% bachelor's+ in 46405 (Lake Station) to 49.9% in 46321 (Munster) — the breadth of educational profiles across the area.

Within Indiana, this is the #2 most populous of 92 counties and ranks #68 for median household income .

Weighted by population, the typical household earns about $76,246 across the county — reflecting what a typical resident sees, not a simple ZIP average.

25.8% of adults age 25+ hold a bachelor's degree or higher (89,330 of 345,919 reporting).

25 Standard delivery, 7 PO Box only, 0 single-entity Unique ZIPs serve this county.

Stories about Lake County


Two counties in one

Median household income spans 4.5× between the wealthiest and poorest ZIPs — a sign of significant intra-county inequality.

Wealthiest ZIP
Saint John
Median income: $127,146
Population: 18,843
Bachelor's+: 42.5%
vs
Poorest ZIP (pop >= 500)
Gary
Median income: $28,526
Population: 8,577
Bachelor's+: 12.9%
For every $1 of household income in 46407, the typical household in 46373 earns $4.46.

All ZIP Codes in Lake County


ZIPCityTypePopulationMedian IncomeArea (sq mi)10-yr Growth
46307Crown PointStandard71,673$107,80087.818.8%
46410MerrillvilleStandard39,243$64,12730.91.4%
46342HobartStandard32,224$75,52136.12.7%
46312East ChicagoStandard26,022$42,12514.3-11.5%
46375ScherervilleStandard24,188$93,16013.22.9%
46321MunsterStandard23,733$110,1877.61.7%
46322HighlandStandard23,680$78,0626.91.1%
46311DyerStandard23,321$116,65212.94.4%
46323HammondStandard23,047$59,6886.2-0.6%
46324HammondStandard21,409$63,0524.4-6.5%
46356LowellStandard19,721$89,217113.911.9%
46373Saint JohnStandard18,843$127,14611.033.7%
46319GriffithStandard17,847$74,6629.6-0.6%
46303Cedar LakeStandard17,680$84,21130.426.3%
46408GaryStandard15,747$47,4539.1-3.6%
46404GaryStandard15,428$42,2566.5-8.9%
46320HammondStandard14,353$37,1584.4-3.6%
46405Lake StationStandard12,184$60,8818.47.1%
46394WhitingStandard11,894$66,1764.6-2.6%
46403GaryStandard10,929$45,99110.0-14.0%
46327HammondStandard10,597$47,2884.7-6.5%
46406GaryStandard9,001$35,83913.4-11.7%
46407GaryStandard8,577$28,5264.4-31.2%
46409GaryStandard7,184$44,6673.5-17.4%
46402GaryStandard5,836$33,5299.7-8.2%
46376SchneiderPO Box319$64,2057.0-5.6%
46377ShelbyPO Box45$38,9580.0-88.8%
46355LeroyPO Box0.0
46308Crown PointPO Box0.0
46411MerrillvillePO Box0.0
46325HammondPO Box0.0
46401GaryPO Box0.0

Adjacent & Nearby Counties