50138 ZIP Code — Knoxville, IA

Marion County, Iowa

ZIP code 50138 is located in Knoxville, Iowa, within Marion County. It covers approximately 168.15 square miles and serves a population of 12,086 residents. This is a standard ZIP code in the Central (CT) timezone, served by area code 641.

About ZIP code 50138

The housing stock consists of predominantly single-family detached homes. Most homes were built in the pre-1940, giving the area an established character. Median home value is $153,600. Owner-occupancy is high at 76%, well above the national average.

Median household income is $65,341. 37% of households receive Social Security income, suggesting a notable retiree or disability population.

The dominant occupation class is management, business, and professional, with manufacturing as the leading industry. The average commute of 22 minutes is near the national average.

Educational attainment is near the national average, with 24% of residents holding a bachelor's degree or higher.

Overall, ZIP code 50138 reflects a community defined by high homeownership and a significant Social Security-dependent population.

12,086

population

168.15

sq mi land

Standard

ZIP type

Central (CT)

timezone

50138 ZIP code map

Cities in ZIP code 50138

Below are the cities the US Postal Service accepts for ZIP code 50138. Using any city not on this list may result in mail delivery delays.

City	Status
Knoxville	Acceptable
Knoxville	Preferred

Nearby ZIP codes

50225 Pleasantville (7.1 mi) 50119 Harvey (10.5 mi) 50214 Otley (10.6 mi) 50256 Tracy (11.9 mi) 50116 Hamilton (12.2 mi) 50139 Lacona (13.5 mi) 50219 Pella (13.6 mi) 50044 Bussey (15.2 mi) 50166 Milo (15.5 mi) 50150 Lovilia (15.7 mi) 50170 Monroe (15.9 mi) 50118 Hartford (17.3 mi)

Demographics updated 05/2026

Population
Total population	12,086
Population density	72 / sq mi
State FIPS	19
County FIPS	125

Geography
Land area	168.15 sq mi
Water area	7.65 sq mi
Latitude	41.3137
Longitude	-93.1348
Timezone	Central (CT)
Area code	641

Total population by age

Gender

Race & ethnicity

Economics updated 05/2026

Household income

Income range	This ZIP	County avg	State avg
Under $50k	41.2%	36.8%	40.1%
$50k – $100k	34.2%	35.2%	33.4%
$100k – $200k	21.4%	22.5%	21.5%
Over $200k	3.2%	5.5%	5.0%

Demographics & statistics

12,086

Population

People per sq mi

42.3

Median age

$65,341

Median household income

$36,306

Per capita income

$153,600

Median home value

$790

Median monthly rent

75.7%

Home ownership

9.9%

Poverty rate

3.0%

Unemployment

4,296

Housing units

24.0%

Bachelor's or higher

Age distribution

Male Female

229

Under 5

257

326

5–9

366

387

10–14

435

368

15–19

413

384

20–24

431

708

25–34

796

577

35–44

650

666

45–54

749

432

55–59

487

377

60–64

424

712

65–74

801

272

75–84

306

251

85+

282

← Male

Female →

Age summary

Group	Count	%
Under 18	2,620	21.7%
18 and over	9,466	78.3%
65 and over	2,624	21.7%
Median age	42.3 years

Race & ethnicity

White 93.9%

Two or more races 4%

Asian 0.6%

Hispanic or Latino 0.6%

Black or African American 0.5%

Other race 0.1%

American Indian / Alaska Native 0.1%

Native Hawaiian / Pacific Islander 0.1%

Group	Count	%
White	11,423	93.9%
Two or more races	483	4%
Asian	78	0.6%
Hispanic or Latino	74	0.6%
Black or African American	66	0.5%
Other race	16	0.1%
American Indian / Alaska Native	10	0.1%
Native Hawaiian / Pacific Islander	10	0.1%

Household income

Income range	This ZIP	County avg	State avg
Under $50k	41.2%	36.8%	40.1%
$50k – $100k	34.2%	35.2%	33.4%
$100k – $200k	21.4%	22.5%	21.5%
Over $200k	3.2%	5.5%	5.0%

Under $10k 3.2%

$10k–$15k 5.8%

$15k–$25k 5.5%

$25k–$35k 8.0%

$35k–$50k 12.9%

$50k–$75k 21.6%

$75k–$100k 14.5%

$100k–$150k 15.6%

$150k–$200k 7.3%

$200k+ 5.5%

Range	% of households
Under $10k	3.2%
$10k–$15k	5.8%
$15k–$25k	5.5%
$25k–$35k	8.0%
$35k–$50k	12.9%
$50k–$75k	21.6%
$75k–$100k	14.5%
$100k–$150k	15.6%
$150k–$200k	7.3%
$200k+	5.5%
Median income	$65,341

Housing

Home values

Under $50k 9.3%

$50k–$100k 18.0%

$100k–$150k 21.1%

$150k–$200k 15.9%

$200k–$300k 18.6%

$300k–$500k 8.8%

$500k–$1M 7.4%

$1M+ 0.8%

Housing overview

Metric	Value
Median home value	$153,600
Median rent / month	$790
Owner occupied	75.7%
Renter occupied	24.3%
Vacant	7.5%
Single-family detached	77.6%
Large apartment buildings	1.1%
Mobile homes	7.6%
Median rooms	5.7
Avg household size (owned)	2.44

Year built

Era	%
2020 or later	0.0%
2010–2019	6.0%
2000–2009	8.9%
1990–1999	12.0%
1980–1989	7.4%
1970–1979	18.3%
1960–1969	13.0%
1950–1959	8.6%
1940–1949	6.2%
1939 or earlier	19.6%

Bedrooms

Size	% of units
No bedroom (studio)	1.2%
1 bedroom	9.7%
2 bedrooms	26.9%
3 bedrooms	42.4%
4 bedrooms	15.6%
5+ bedrooms	4.2%

Vehicles per household

Vehicles	% of households
No vehicle	5.3%
1 vehicle	31.3%
2 vehicles	36.6%
3 or more	26.8%

Heating fuel

Fuel type	%
Utility gas	63.5%
Electricity	17.6%
Propane / LP gas	16.7%
Wood	0.9%

Households & families

Household type	Count	%
Married-couple family	2,806	54.7%
Cohabiting couple	371	7.2%
Male householder, no spouse	848	16.5%
Female householder, no spouse	1,101	21.5%
Households with children under 18	1,623	31.7%
Households with seniors (65+)	1,738	33.9%
Average household size	2.31

Marital status

Status	Male	Female
Never married	26.3%	20.2%
Married	58.6%	54.3%
Separated	0.7%	1.4%
Widowed	3.4%	8.3%
Divorced	11.0%	15.9%

Education

Less than 9th grade 1.3%

Some HS, no diploma 5.1%

HS graduate 37.3%

Some college, no degree 21.3%

Associate's degree 11.0%

Bachelor's degree 17.5%

Graduate / professional 6.5%

Metric	%
HS diploma or higher	93.6%
Bachelor's or higher	24.0%

School enrollment (ages 3–17)

Type	Count	%
Nursery / preschool	76	2.9%
Kindergarten	148	5.6%
Elementary school	1,258	47.6%
High school	714	27.0%
College / grad school	445	16.8%

Employment

Industry of employment

Manufacturing 25.4%

Education & healthcare 21.3%

Retail trade 10.3%

Finance & real estate 7.3%

Transportation & utilities 6.7%

Arts, food & hospitality 6.5%

Other services 4.7%

Construction 4.3%

Public administration 4.2%

Agriculture & mining 3.3%

Professional & management 3.3%

Information 2.3%

Wholesale trade 0.4%

Occupation

Category	%
Management, business & arts	29.1%
Service	14.4%
Sales & office	20.8%
Natural resources & construction	9.3%
Production & transportation	26.5%

Employment type

Type	%
Private sector	82.6%
Government	12.1%
Self-employed	5.3%
Unpaid family workers	0.0%

Commute

Method	%
Drive alone	82.3%
Carpool	7.0%
Public transit	0.0%
Walk	1.2%
Work from home	7.2%
Other means	2.4%
Avg commute (minutes)	22.3

Poverty

All people 9.9%

Under 18 years 11.5%

18 and over 9.4%

Married-couple families 2.9%

Female-led households 23.6%

Income support

Source	% of households
Social Security	37.2%
Retirement income	26.6%
Supplemental Security	3.8%
Cash public assistance	1.9%
Food stamps / SNAP	11.4%

Health indicators

Condition	%
Obesity	34.6%
High blood pressure	34.2%
High cholesterol	33.7%
Diabetes	10.2%
Heart disease	7.0%
Stroke	3.1%
Asthma	9.3%
Arthritis	26.4%
Kidney disease	2.9%
Pulmonary disease	6.9%
Cancer	7.5%

Behavior / access	%
Smoking	17.7%
Binge drinking	20.6%
No physical activity	24.0%
Less than 7 hrs sleep	31.7%
Depression	17.7%
Fair or poor health	12.6%
Poor mental health	13.1%
Poor physical health	9.8%
No health insurance	9.2%
Visited doctor (checkup)	76.1%
Visited dentist	71.9%
Cholesterol screening	89.0%
Teeth loss	12.3%

Veterans & disability

Veterans	Count	%
Civilian veterans	970	10.3%

Disability	%
Any disability	18.6%
Under 18	3.4%
18–64 years	15.7%
65 and over	42.5%

Health insurance coverage

Type	%
Private insurance	71.2%
Public insurance	43.9%
No insurance	3.7%
Uninsured under 19	2.5%

Language & origin

Language spoken at home (age 5+)

Language	Count	%
English only	11,600	96.0%
Spanish	89	0.8%
Other Indo-European	58	0.5%
Asian & Pacific Islander	31	0.3%
Other languages	0	0.0%

Place of birth & citizenship

Origin	Count	%
Native born (US)	11,911	98.6%
Born in same state	11,882	98.3%
Born in different state	9,327	77.2%
Foreign born	29	0.2%
Naturalized citizen	175	1.4%
Not a US citizen	133	76.0%

Ancestry

Ancestry	Count	%
Italian	1,586	13.1%
French	1,558	12.9%
English	1,012	8.4%
Arab	984	8.1%

Ancestry	Count	%
Polish	530	4.4%
Dutch	47	0.4%
Irish	9	0.1%

Technology access

Metric	% of households
Computer access	42.4%
Internet access	89.1%

Source: U.S. Census Bureau, American Community Survey 2025 estimates.

Frequently asked questions about ZIP code 50138

What city is ZIP code 50138 in?

ZIP code 50138 is primarily assigned to Knoxville, Iowa.

What county is ZIP code 50138 in?

ZIP code 50138 falls within Marion County, Iowa.

Does ZIP code 50138 have a large retiree population?

37% of households in ZIP code 50138 receive Social Security income, suggesting a significant retiree or disability population.

What is the typical home value in ZIP code 50138?

The median home value in ZIP code 50138 is $153,600.

Does ZIP code 50138 have a large veteran population?

10% of civilians in ZIP code 50138 are veterans, above the national average of ~7%.

What is the population of ZIP code 50138?

ZIP code 50138 has an estimated population of 12,086 residents, with a density of 72 people per square mile.

What timezone is ZIP code 50138 in?

ZIP code 50138 observes the CST timezone.