Boulder County, Colorado

County in CO, US

By Neilsberg Research

Last updated May 1, 2026

Key Indicators

A quick look at key numbers

Population

328,961

Source: U.S. Census Bureau American Community Survey (ACS) 2020-2024 5-Year Estimates

Median Age

37.7

years ∙ half population younger than 37.7, half older

Diversity Index

41.9%

chance two random people differ in race and ethnicity

Nativity

10.1%

foreign-born population

89.9%Native

10.1% Foreign-born

Geographic Context

Location, size, and surroundings

About

Boulder County is a county in Colorado, United States.

Location

County in CO, US

Co-ordinates

DEC40.094971° N, 105.397710° W

DMS40° 05′ 41.90″ N, 105° 23′ 51.76″ W

Population Density & area

452.9/sq mi (174.8/km²)

Total Area

740.5 sq mi (1,917.8 km²)

Land Area

726.4 sq mi (1,881.4 km²) · 98.1%

Water Area

14.1 sq mi (36.4 km²) · 1.9%

Demographics & Living

Who lives here, how households are formed, and community composition

Population Composition

Key characteristics of the population

Sex Distribution

50.4% male

Male 50.4%

Female 49.6%

males per 100 females

Boulder County 101.7

Colorado 102.6

United States 98

Nativity

10.1%

foreign-born population

89.9%Native

10.1% Foreign-born

% Foreign-born

Boulder County 10.1%

Colorado 9.8%

United States 14.1%

Age Distribution

How the population is spread across age groups

Median Age

37.7

years ∙ half population younger than 37.7, half older

Boulder County

37.7

Colorado

37.7

United States

38.9

Dependency ratio

51.4

dependents per 100 working-age adults

Boulder County 51.4

Colorado 57.7

United States 64.4

AGE DISTRIBUTION

Distribution of age group

Median age

	Boulder County	Colorado	United States
Age Group
Children (Under 18)	17.5%	21%	22%
Working age (18-64)	66.1%	63.4%	60.8%
Senior (65+)	16.4%	15.6%	17.2%
Dependency ratio
Total dependency ratio	51.4	57.7	64.4
Child dependency ratio	26.6	33.1	36.1
Old-age dependency ratio	24.8	24.6	28.3

Racial & Ethnic Composition

Racial and ethnic makeup and how it compares

Race & Ethnicity

White

74.5%

Black

0.8%

Asian

4.7%

Hispanic

14.7%

Other

5.3%

Note: White, Black, and Asian refer to individuals belonging to a single race and not of Hispanic origin. Hispanics may be of any race.

Diversity Index

41.9%

chance two random people differ in race and ethnicity

Boulder County 41.9%

Colorado 52.5%

United States 61.4%

Note: The Diversity Index (DI), based on the Blau Index, measures the probability that two randomly selected individuals differ in race and ethnicity. Values range from 0 (no diversity) to 1 (high diversity) and are shown as percentages.

RACIAL & ETHNIC COMPOSITION

Race & Ethnicity

Percentage of Boulder County population

	Boulder County	Colorado	United States
Hispanic or Latino	14.7%	22.5%	19.3%
Mexican	9.9%	15.8%	11.3%
Puerto Rican	0.5%	0.7%	1.8%
Cuban	0.2%	0.3%	0.8%
Other Hispanic / Latino	4.1%	5.7%	5.5%
Not Hispanic or Latino	85.3%	77.5%	80.7%
One race	80.5%	72.9%	76.4%
White	74.5%	64.8%	57.4%
Black or African American	0.8%	3.8%	11.9%
American Indian and Alaska Native	0.2%	0.4%	0.5%
Asian	4.7%	3.2%	5.9%
Native Hawaiian and Other Pacific Islander	0.1%	0.1%	0.2%
Some Other Race	0.3%	0.5%	0.6%
Two or more races (Multiracial)	4.8%	4.6%	4.3%

Household & Families Composition

Household size, type, and family structure

Household structure

55% family

Family 55%

Non family 45%

% family households

Boulder County 55%

Colorado 61.7%

United States 64.2%

Average household size

2.3

persons per household

Boulder County

2.3

Colorado

2.42

United States

2.53

Household & Family COMPOSITION

Households

Percentage of Boulder County population

	Boulder County	Colorado	United States
Total households	137,008	2,374,218	129,227,496
Average houshold size	2.3	2.42	2.53
Family households	75,286	1,465,097	82,990,528
Average family size	2.9	3.01	3.14
Married couple family	60,534	1,147,437	60,637,388
Other families	14,752	317,660	22,353,140
Male householder	5,576	106,780	6,572,819
Female householder	9,176	210,880	15,780,321
Non-family households	61,722	909,121	46,236,968
One-person households	41,209	679,604	37,140,836
Male householder	20,033	330,797	16,871,444
Senior (65+) living alone	5,172	88,830	5,225,110
Female householder	21,176	348,807	20,269,392
Senior (65+) living alone	10,967	157,958	10,089,070
Other living arrangements	20,513	229,517	9,096,132

Housing Profile

Housing stock, ownership, rentals, and cost burdens

Total housing units

144,729

housing units

Boulder County 144,729

Colorado 2,589,053

United States 143,775,355

Occupancy status

94.7% occupied

Occupied 94.7%

Vacant 5.3%

vacancy rate

Boulder County 5.3%

Colorado 8.3%

United States 10.1%

Housing Characteristics

How the housing supply is structured and used

Types of Housing unit

66%

Single family houses

66%

Apartments in multi-unit structures

31.7%

Mobile homes

2.3%

Boat, RV, van, etc

0.1%

Median Year Built

1986

Half of houses were built before 1986, and half after.

Historic ∙ 1939 or earlier

5.9%

Postwar & mid-century ∙ 1940 - 1969

16.7%

Late 20th century ∙ 1970 - 1999

51.6%

Modern ∙ 2000 or later

25.8%

Note: Median year built reflects occupied units only; distribution includes all units.

Housing Characteristics

Units, rooms & bedrooms

Physical characteristics of housing units

	Boulder County	Colorado	United States
Rooms per unit
Median rooms	5.8	5.7	5.5
1–3 rooms	20.1%	17.3%	15.1%
4–6 rooms	38.7%	43.7%	51.6%
7+ rooms	41.3%	39.1%	33.4%
Bedrooms
No bedroom / studio	2.7%	2.7%	2.9%
1 bedroom	12.7%	11.7%	10.9%
2 bedrooms	24%	24.1%	25%
3 bedrooms	29.7%	32.3%	38.7%
4+ bedrooms	30.9%	29.2%	22.4%
At a glance
Median year built	1986	1988	1981
Total housing units	144,729	2,589,053	143,775,355

Occupancy Profile

Who is inside and how they use it

Homeownership

62% owners

Renter-occupied 38%

Owner-occupied 62%

homeownership rate

Boulder County 62%

Colorado 66.2%

United States 65.2%

Average household size

2.44

Owner-occupied

2.07

Renter-occupied

owner-occupied average size

Boulder County 2.44

Colorado 2.56

United States 2.64

Housing Characteristics

Occupied unit characteristics

Tenure, crowding, and utilities

	Boulder County	Colorado	United States
Total occupied units	137,008	2,374,218	129,227,496
Year moved in
2020 or later	32.9%	30.5%	24.8%
2010 to 2019	37.1%	41%	39.6%
2000 to 2009	15.3%	14.8%	16.4%
1999 or earlier	14.8%	13.8%	19.1%
Occupants per room
1.00 or fewer	98.4%	97.6%	96.6%
1.01 to 1.50	1.1%	1.6%	2.2%
1.51 or more	0.5%	0.8%	1.2%
Vehicles availability
No vehicles	5.2%	5.2%	8.4%
1 vehicle	33.8%	30.7%	33.1%
2 vehicles	39.2%	38.8%	36.6%
3 or more vehicles	21.8%	25.4%	21.9%
House heating fuel used
Gas	72.3%	71.3%	51.4%
Electricity	24.8%	25.6%	41.3%
Solar	0.8%	0.5%	0.3%
Fuel oil, kerosene etc	0.2%	0.1%	3.9%
All other fuels	1.5%	2%	2%
No fuel used	0.5%	0.5%	1.2%
Selected characteristics
Lacking complete plumbing	0.3%	0.3%	0.4%
Lacking complete kitchen	0.6%	0.7%	0.8%
No telephone service available	0.5%	0.7%	0.9%

Housing Value

What owner-occupied units are worth

Median home value

$756,300

owner-occupied units

Median value(USD)

Boulder County

$756,300

Colorado

$539,400

United States

$332,700

Housing Cost Burden

27.9%

of homeowners with a mortgage are cost-burdened

% Cost-Burdened Households

Owners with a mortgage

27.9%

Owners without a mortgage

15.3%

Renters

59.9%

Note: Households spending 30% or more of their income on housing costs are considered cost-burdened.

Financial characteristics

Property value and housing costs

Tenure, crowding, and utilities

	Boulder County	Colorado	United States
Property value
Median Value	$756,300	$539,400	$332,700
Under $100,000	3.9%	4.8%	11.4%
$100,000 - $200,000	1.4%	3.6%	15.8%
$200,000 - $300,000	1.7%	6.8%	17.8%
$300,000 - $500,000	14.9%	30%	26.9%
$500,000 - $1,000,000	48.8%	43.6%	20.9%
$1,000,000 and more	29.3%	11.1%	7.1%
Owner-occupied households
With a mortgage	66.1%	69.4%	60.6%
Without a mortgage	33.9%	30.6%	39.4%
Median monthly owner costs
With a mortgage	$2,743	$2,326	$1,963
Without a mortgage	$836	$663	$638
Gross rent
Median rent	$1,966	$1,761	$1,413

Education Profile

How educated is the community and how education pays off

Adults with a college degree

64.2%

of adults 25+ with a bachelor's degree or higher

Boulder County 64.2%

Colorado 45.7%

United States 35.7%

Adults without a high school diploma

4.2%

of adults (25+) without a high school diploma

Boulder County 4.2%

Colorado 7.1%

United States 10.4%

School Enrollment

Who is enrolled in school and at what level

School enrollment

94,605

population (age 3+) enrolled in school

Nursery / Preschool

5.2%

K–12

48.3%

College / Undergraduate

36.8%

Graduate / Professional

9.7%

College-going rate (18-24 yr olds)

65.6%

of 18-24-year-olds in college or graduate school

Boulder County

65.6%

Colorado

38%

United States

40.9%

Enrollment & school type

Enrollment levels, college-going rate, and public vs private school split

Population 3+ currently enrolled in a school

	Boulder County	Colorado	United States
Total enrolled (age 3+)	94,605	1,369,681	80,089,790
Nursery / preschool	5.2%	5.9%	5.7%
K–12	48.3%	66.5%	67.6%
Kindergarten	3.1%	4.5%	5%
Elementary: Grades 1–4	13.6%	19.4%	19.8%
Elementary: Grades 5–8	14.7%	20.9%	21%
High School: Grades 9–12	16.8%	21.7%	21.7%
College or graduate school	46.5%	27.6%	26.7%
College, undergraduate	36.8%	21%	21%
Graduate, professional school	9.7%	6.6%	5.8%
College-going rate · 18-24 yr olds	65.6%	38%	40.9%
School type
Public school	88.5%	86%	82%
Private school	11.5%	14%	18%

Education Attainment by Level & Gender

What is the highest level of education completed among adults

Education attainment

220,629

population 25 years and over

Total adults (25+)

Less than 9th grade

9th-12th, no diploma

2.2%

HS graduate

11.3%

Some college no degree

14.7%

Associates degree

5.7%

Bachelors degree

34.2%

Graduate or professional degree

30%

Attainment by gender

Male vs Female

Adults (25+) · Share within each education level

% male · % female

Less than 9th grade

47.4% · 52.6%

9th-12th, no diploma

56.7% · 43.3%

HS graduate

50% · 50%

Some college no degree

53.6% · 46.4%

Associates degree

48% · 52%

Bachelors degree

49.7% · 50.3%

Graduate or professional degree

48.9% · 51.1%

Educational Attainment Overview

Distribution and key education attainment rates for adults (25+)

Highest credential completed · adults 25+

	Boulder County	Colorado	United States
Population (25+)	220,629	4,095,727	230,807,303
Less than 9th grade	2%	3.1%	4.7%
9th–12th, no diploma	2.2%	4%	5.7%
High school diploma or GED	11.3%	19.7%	26%
Some college, no degree	14.7%	19.2%	19.1%
Associate's degree	5.7%	8.3%	8.8%
Bachelor's degree or higher	64.2%	45.7%	35.7%
Bachelor's degree	34.2%	28.1%	21.6%
Graduate or professional	30%	17.6%	14.1%
High School or higher	95.8%	92.9%	89.6%

Earnings by education level

percentage as applicable

Median Earnings

$67,063

Median earnings for adults 25+, by level

Less than HS graduate

$40,630

HS graduate

$43,159

Some college or associates

$47,920

Bachelors degree

$75,096

Graduate or professional degree

$97,099

Poverty Rate

4.1%

for ages 25+, with bachelors degree or higher

Less than HS graduate

19%

HS graduate

11.5%

Some college or associates

10.7%

Bachelors degree or higher

4.1%

Outcomes by Education Level

Earnings and poverty rates across education levels (25+)

Adults 25+

	Boulder County	Colorado	United States
Median earnings
Population 25+, with earnings	$67,063	$60,455	$52,696
Less than high school graduate	$40,630	$37,820	$32,485
High school graduate (includes equivalency)	$43,159	$45,140	$40,153
Some college or associate's degree	$47,920	$50,210	$47,260
Bachelor's degree	$75,096	$73,999	$70,044
Graduate or professional degree	$97,099	$90,992	$90,720
Poverty rates
Less than high school graduate	19%	19.9%	24.2%
High school graduate (includes equivalency)	11.5%	11.5%	14.4%
Some college or associate's degree	10.7%	8.8%	9.8%
Bachelor's degree or higher	4.1%	3.9%	4.5%

Insights for Boulder County, by topic

Income By year By race By age By gender

Population By year By race By age By gender

About Neilsberg Research

Neilsberg Research team are data scientists with expertise in processing, analysis and visualization of big data helping small businesses make right decisions.

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